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Evolutionary Psychology

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Evolutionary Psychology (EVP) is an open access , peer-reviewed journal which focuses on original, empirical research addressing human psychology guided by an evolutionary perspective. Please see the Aims and Scope tab for further information.

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Evolutionary Psychology publishes both (a) original, empirical research articles and (b) theoretical and review articles addressing human psychology guided by an evolutionary perspective. The journal aspires to attract as readers faculty, students, and researchers from across the social, behavioral, and life sciences who have an interest in applying evolutionary perspectives to psychology and behavior.

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Research topics at the Center for Evolutionary Psychology

Reprints are provided for scholarly purposes only.  Permission to reprint any article must be sought from the holder of the copyright. 

Scientists at the Center for Evolutionary Psychology specialize in finding new ways that an evolutionary perspective can inform research on the design of the human mind.  In so doing, we have been researching many new topics, as well as trying out new approaches to old topics.  Below we provide a partial list with links to some relevant research papers. 

Principles of evolutionary psychology

A roadmap to principles of evolutionary psychology

Reasoning and rationality

Social exchange reasoning (reciprocation, reciprocal altruism, cooperation)

Judgment under uncertainty  (intuitive statistics; optimal foraging; ecological rationality; heuristics & biases)

Adaptationism, normative theories, and rationality

Emotions—What are they?

Emotion  (emotions as super-ordinate programs solving the problem of mechanism coordination in a multimodular mind)

Emotions—Specific ones

Anger . See also:

Formidability, Strength, and Entitlement . Adaptations for detecting physical strength

Vision and Visual Attention

Visual attention –a system specialized for monitoring animals

Vision : Faces—the case for domain-specific object recognition

Evolutionary Biology

Evolutionary Biology : Intragenomic Conflict , Pathogens & the Evolution of Sexual Recombination; Banker’s Paradox (etc)

Literature and the Arts

Art, Fiction, and Aesthetics

Close social relationships

Kin detection  (as regulator of incest avoidance; altruism)

Friendship and Deep Engagement Relationships

Courtship, Mate Choice, and Human Sexuality

Varieties of Cooperation

Two-person cooperation / reciprocation / reciprocal altruism

Evolution of generosity

Cooperating in Groups:

Coalitional psychology and alliance detection

Adaptations for collective action

Memory  (memory systems; specializations; personality trait database; self-knowledge, episodic memories; amnesia; memory loss )

Spatial cognition

Spatial adaptations for foraging (female advantage in location memory for plants; content effects; optimal foraging)

Tools: Cognitive foundations

Adaptations for tool use  (the artifact concept and inferences about function; design stance; problem solving, dissociation between inferences about function and naming)

Personality

Personality (personality differences and universal human nature; adaptationist framework for personality science; cognitive systems specialized for encoding, storing, and retrieving knowledge of personality traits)

The links below are not live yet—hopefully I will be able to update them soon! LC

Darwinian medicine, Darwinian psychiatry

Development

Economics, Business, and Organizational Behavior

Hazard Management (precautionary reasoning)

Intelligence (improvisational intelligence; dedicated intelligence; decoupled reasoning (counterfactual reasoning, suppositional reasoning, metarepresentation)

Theoretical foundations of psychology and the behavioral sciences

Environments of Evolutionary Adaptedness  (EEA; Why the past explains the present)

Evolutionary psychology: A primer

A brief introduction to the field in  [ English ], [ Español ] and [ Português ].

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• DOI: 10.1037/amp0000849
• Corpus ID: 244132848

Evolving evolutionary psychology.

• D. Narvaez , D. Moore , +2 authors R. Lickliter
• Published in American Psychologist 15 November 2021

15 Citations

The road not taken: what developmental psychology might learn from darwin’s insights concerning sexual selection, towards a biologically coherent account of the brain and how it develops, returning to evolved nestedness, wellbeing, and mature human nature, an ecological imperative, the evolved nest, oxytocin functioning, and prosocial development, basic emotions or constructed emotions: insights from taking an evolutionary perspective., cultural-historical activity theory and its contemporary import: ideas emerging in context and time., making sense of the modularity debate, molecular and systemic epigenetic inheritance: integrating development, genetics, and evolution, beyond belongingness: rethinking innate behavioral predispositions, learning constraints, and cognitive capacities, on the evolution of epigenetics via exaptation: a developmental systems perspective, 148 references, evolutionary theory meets cognitive psychology: a more selective perspective, from computers to cultivation: reconceptualizing evolutionary psychology, evolutionary psychology. controversies, questions, prospects, and limitations..

• Highly Influential

Integrating Development and Evolution in Psychological Science: Evolutionary Developmental Psychology, Developmental Systems, and Explanatory Pluralism

A developmental evolutionary framework for psychology, darwin in mind: new opportunities for evolutionary psychology, evolutionary psychology as maladapted psychology, evolutionary psychology: a how-to guide, synthesis in the human evolutionary behavioural sciences, is evolutionary psychology a metatheory for psychology a discussion of four major issues in psychology from an evolutionary developmental perspective, related papers.

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Evolutionary Psychology

Evolutionary psychology is one of many biologically informed approaches to the study of human behavior. Along with cognitive psychologists, evolutionary psychologists propose that much, if not all, of our behavior can be explained by appeal to internal psychological mechanisms. What distinguishes evolutionary psychologists from many cognitive psychologists is the proposal that the relevant internal mechanisms are adaptations—products of natural selection—that helped our ancestors get around the world, survive and reproduce. To understand the central claims of evolutionary psychology we require an understanding of some key concepts in evolutionary biology, cognitive psychology, philosophy of science and philosophy of mind. Philosophers are interested in evolutionary psychology for a number of reasons. For philosophers of science —mostly philosophers of biology—evolutionary psychology provides a critical target. Although here is a broad consensus among philosophers of biology that evolutionary psychology is a deeply flawed enterprise, this does not entail that these philosophers completely reject the relevance of evolutionary theory to human psychology. For philosophers of mind and cognitive science evolutionary psychology has been a source of empirical hypotheses about cognitive architecture and specific components of that architecture. However, some philosophers of mind are also critical of evolutionary psychology but their criticisms are not as all-encompassing as those presented by philosophers of biology. Evolutionary psychology is also invoked by philosophers interested in moral psychology both as a source of empirical hypotheses and as a critical target.

In what follows I briefly explain evolutionary psychology’s relations to other work on the biology of human behavior and the cognitive sciences. Next I introduce the research tradition’s key theoretical concepts. In the following section I take up discussions about evolutionary psychology in the philosophy of mind, specifically focusing on the debate about the massive modularity thesis. I go on to review some of the criticisms of evolutionary psychology presented by philosophers of biology and assess some responses to those criticisms. I then go on to introduce some of evolutionary psychology’s contributions to moral psychology and human nature and, finally, briefly discuss the reach and impact of evolutionary psychology.

1. Evolutionary Psychology: One research tradition among the various biological approaches to explaining human behavior

2. evolutionary psychology’s theory and methods, 3. the massive modularity hypothesis, 4. philosophy of biology vs. evolutionary psychology, 5. moral psychology and evolutionary psychology, 6. human nature, 7. applications of evolutionary psychology and prospects for further debate, other internet resources, related entries.

This entry focuses on the specific approach to evolutionary psychology that is conventionally named by the capitalized phrase “Evolutionary Psychology”. This naming convention is David Buller’s (2000; 2005) idea. He introduces the convention to distinguish a particular research tradition (Laudan 1977) from other approaches to the biology of human behavior. [ 1 ] This research tradition is the focus here but lower case is used throughout as no other types of evolutionary psychology are discussed. Evolutionary psychology rests upon specific theoretical principles (presented in section 2 below) not all of which are shared by others working in the biology of human behavior (Laland & Brown 2002; Brown et al. 2011). For example, human behavioral ecologists present and defend explanatory hypotheses about human behavior that do not appeal to psychological mechanisms (e.g., Hawkes 1990; Hrdy 1999). Behavioral ecologists also believe that much of human behavior can be explained by appealing to evolution while rejecting the idea held by evolutionary psychologists that one period of our evolutionary history is the source of all our important psychological adaptations (Irons 1998). Developmental psychobiologists take yet another approach: they are anti-adaptationist. (Michel & Moore 1995; but see Bateson & Martin 1999; Bjorklund & Hernandez Blasi 2005 for examples of developmentalist work in an adaptationist vein.) These theorists believe that much of our behavior can be explained without appealing to a suite of specific psychological adaptations for that behavior. Instead they emphasize the role of development in the production of various human behavioral traits. From here on, “evolutionary psychology” refers to a specific research tradition among the many biological approaches to the study of human behavior.

Paul Griffiths argues that evolutionary psychology owes theoretical debt to both sociobiology and ethology (Griffiths 2006; Griffiths 2008). Evolutionary psychologists acknowledge their debt to sociobiology but point out that they add a dimension to sociobiology: psychological mechanisms. Human behaviors are not a direct product of natural selection but rather the product of psychological mechanisms that were selected for. The relation to ethology here is that in the nineteen fifties, ethologists proposed instincts or drives that underlie our behavior; [ 2 ] evolutionary psychology’s psychological mechanisms are the correlates to instincts or drives. Evolutionary psychology is also related to cognitive psychology and the cognitive sciences. The psychological mechanisms they invoke are computational, sometimes referred to as “Darwinian algorithms” or as “computational modules”. This overt cognitivism sets evolutionary psychology apart from much work in the neurosciences and from behavioral neuroendocrinology. In these fields internal mechanisms are proposed in explanations of human behavior but they are not construed in computational terms. David Marr’s (e.g., 1983) well known three part distinction is often invoked to distinguish the levels at which researchers focus their attention in the cognitive and neurosciences. Many neuroscientists and behavioral neuroendocrinologists work at the implementation level while cognitive psychologists work at the level of the computations that are implemented at the neurobiological level (see Griffiths 2006).

Evolutionary psychologists sometimes present their approach as potentially unifying, or providing a foundation for, all other work that purports to explain human behavior (e.g., Tooby & Cosmides 1992). This claim has been met with strong skepticism by many social scientists who see a role for a myriad of types of explanation of human behavior, some of which are not reducible to biological explanations of any sort. This discussion hangs on issues of reductionism in the social sciences. (Little 1991 has a nice introduction to these issues.) There are also reasons to believe that evolutionary psychology neither unifies nor provides foundations for closely neighboring fields such as behavioral ecology or developmental psychobiology. (See the related discussion in Downes 2005.) In other work, evolutionary psychologists present their approach as being consistent with or compatible with neighboring approaches such as behavioral ecology and developmental psychobiology. (See Buss’s introduction to Buss 2005.) The truth of this claim hangs on a careful examination of the theoretical tenets of evolutionary psychology and its neighboring fields. We now turn to evolutionary psychology’s theoretical tenets and revisit this discussion in section 4 below.

Influential evolutionary psychologists, Leda Cosmides and John Tooby, provide the following list of the field’s theoretical tenets (Tooby & Cosmides 2005):

• The brain is a computer designed by natural selection to extract information from the environment.
• Individual human behavior is generated by this evolved computer in response to information it extracts from the environment. Understanding behavior requires articulating the cognitive programs that generate the behavior.
• The cognitive programs of the human brain are adaptations. They exist because they produced behavior in our ancestors that enabled them to survive and reproduce.
• The cognitive programs of the human brain may not be adaptive now; they were adaptive in ancestral environments.
• Natural selection ensures that the brain is composed of many different special purpose programs and not a domain general architecture.
• Describing the evolved computational architecture of our brains “allows a systematic understanding of cultural and social phenomena” (16–18).

Tenet 1 emphasizes the cognitivism that evolutionary psychologists are committed to. 1 in combination with 2 directs our attention as researchers not to parts of the brain but to the programs run by the brain. It is these programs—psychological mechanisms—that are products of natural selection. While they are products of natural selection, and hence adaptations, these programs need not be currently adaptive. Our behavior can be produced by underlying psychological mechanisms that arose to respond to particular circumstances in our ancestors’ environments. Tenet 5 presents what is often called the “massive modularity thesis” (see, e.g., Samuels 1998; Samuels 2000). There is a lot packed into this tenet and we will examine this thesis in some detail below in section 3. In brief, evolutionary psychologists maintain that there is an analogy between organs and psychological mechanisms or modules. Organs perform specific functions well and are products of natural selection. There are no general purpose organs, hearts pump blood and livers detoxify the body. The same goes for psychological mechanisms; they arise as responses to specific contingencies in the environment and are selected for to the extent that they contribute to the survival and reproduction of the organism. Just as there are no general purpose organs, there are no general purpose psychological mechanisms. Finally, tenet 6 introduces the reductionist or foundational vision of evolutionary psychology, discussed above.

There are numerous examples of the kinds of mechanisms that are hypothesized to underlie our behavior on the basis of research guided by these theoretical tenets: the cheater-detection module; the mind-reading module; the waist/hip ratio detection module; the snake fear module and so on. A closer look at the waist/hip ratio detection module illustrates the above theoretical tenets at work. Devendra Singh (Singh 1993; Singh & Luis 1995) presents the waist/hip ratio detection module as one of the suite of modules that underlies mate selection in humans. This one is a specifically male psychological mechanism. Men detect variations in waist/hip ratio in women. Men’s preferences are for women with waist/hip ratios closer to .7. Singh claims that the detection and preference suite are adaptations for choosing fertile mates. So our mate selection behavior is explained in part by the underlying psychological mechanism for waist/hip ratio preference that was selected for in earlier human environments.

What is important to note about the research guided by these theoretical tenets above is that all behavior is best explained in terms of underlying psychological mechanisms that are adaptations for solving a particular set of problems that humans faced at one time in our ancestry. Also, evolutionary psychologists stress that the mechanisms they focus on are universally distributed in humans and are not susceptible to much, if any, variation. They maintain that the mechanisms are a product of adaptation but are no longer under selection (Tooby & Cosmides 2005, 39–40). Clark Barrett’s (2015) accessible and wide ranging introduction to evolutionary psychology sustains this emphasis on evolved mechanisms as the main focus of evolutionary psychology research. Barrett also expands the scope of evolutionary psychology and notes the addition of research methods developed since Cosmides and Tooby first set out the parameters for research in the field. Some of Barrett’s proposals are discussed in sections 6 and 7 below. Todd Shackleford and Viviana Weekes-Shackleford (2017) have just completed a huge compendium of work in the evolutionarily based psychological sciences. In this volume a vast array of different research methods are presented and defended and there are a number of entries comparing the merits of alternative approaches to evolutionary psychology.

The methods for testing hypotheses in evolutionary psychology come mostly from psychology. For example, in Singh’s work, male subjects are presented with drawings of women with varying waist hip ratios and ask to give their preference rankings. In Buss’s work supporting several hypothesized mate selection mechanisms, he performed similar experiments on subjects, asking for their responses to various questions about features of desired mates (Buss 1990). Buss, Singh and other evolutionary psychologists emphasize the cross cultural validity of their results, claiming consistency in responses across a wide variety of human populations. (But see Yu & Shepard 1998; Gray et al. 2003 for alternate conflicting results to Singh’s.) For the most part standard psychological experimental methods are used to test hypotheses in evolutionary psychology. This has raised questions about the extent to which the evolutionary component of evolutionary psychologists’ hypotheses is being tested (see, e.g., Shapiro & Epstein 1998; Lloyd 1999; Lloyd & Feldman 2002). A response profile may be prevalent in a wide variety of subject populations but this says nothing about whether or not the response profile is a psychological mechanism that arose from a particular selective regimen.

Claims that the mind has a modular architecture, and even massively modular architecture, are widespread in cognitive science (see, e.g., Hirshfield & Gelman 1994). The massive modularity thesis is first and foremost a thesis about cognitive architecture. As defended by evolutionary psychologists, the thesis is also about the source of our cognitive architecture: the massively modular architecture is the result of natural selection acting to produce each of the many modules (see, e.g., Barrett & Kurzban 2006; Barrett 2012). Our cognitive architecture is composed of computational devices, that are innate and are adaptations (Samuels 1998; Samuels et al. 1999a; Samuels et al. 1999b; Samuels 2000). This massively modular architecture accounts for all of our sophisticated behavior. Our successful navigation of the world results from the action of one or more of our many modules.

Jerry Fodor was the first to mount a sustained philosophical defense of modularity as a theory of cognitive architecture (Fodor 1983). His modularity thesis is distinct from the massive modularity thesis in a number of important ways. Fodor argued that our “input systems” are modular—for example, components of our visual system, our speech detection system and so on—these parts of our mind are dedicated information processors, whose internal make-up is inaccessible to other related processors. The modular detection systems feed output to a central system, which is a kind of inference engine. The central system, on Fodor’s view is not modular. Fodor presents a large number of arguments against the possibility of modular central systems. For example, he argues that central systems, to the extent that they engage in something like scientific confirmation, are “Quinean” in that “the degree of confirmation assigned to any given hypothesis is sensitive to properties of the entire belief system” (Fodor 1983, 107). Fodor draws a bleak conclusion about the status of cognitive science from his examination of the character of central systems: cognitive science is impossible. So on Fodor’s view, the mind is partly modular and the part of the mind that is modular provides some subject matter for cognitive science.

A distinct thesis from Fodor’s, the massive modularity thesis, gets a sustained philosophical defense from Peter Carruthers (see especially Carruthers 2006). Carruthers is well aware that Fodor (see e.g. Fodor 2000) does not believe that central systems can be modular but he presents arguments from evolutionary psychologists and others that support the modularity thesis for the whole mind. Perhaps one of the reasons that there is so much philosophical interest in evolutionary psychology is that discussions about the status of the massive modularity thesis are highly theoretical. [ 3 ] Both evolutionary psychologists and philosophers present and consider arguments for and against the thesis rather than simply waiting until the empirical results come in. Richard Samuels (1998) speculates that argument rather than empirical data is relied on, because the various competing modularity theses about central systems are hard to pull apart empirically. Carruthers exemplifies this approach as he relies heavily on arguments for massive modularity often at the expense of specific empirical results that tell in favor of the thesis.

There are many arguments for the massive modularity thesis. Some are based upon considerations about how evolution must have acted; some are based on considerations about the nature of computation and some are versions of the poverty of the stimulus argument first presented by Chomsky in support of the existence of an innate universal grammar. (See Cowie 1999 for a nice presentation of the structure of poverty of the stimulus arguments.) Myriad versions of each of these arguments appear in the literature and many arguments for massive modularity mix and match components of each of the main strands of argumentation. Here we review a version of each type of argument.

Carruthers presents a clear outline of the first type of argument “the biological argument for massive modularity”: “(1) Biological systems are designed systems, constructed incrementally. (2) Such systems, when complex, need to have massively modular organization. (3) The human mind is a biological system and is complex. (4) So the human mind will be massively modularly in its organization” (Carruthers 2006, 25). An example of this argument is to appeal to the functional decomposition of organisms into organs “designed” for specific tasks, e.g. hearts, livers, kidneys. Each of these organs arises as a result of natural selection and the organs, acting together, contribute to the fitness of the organism. The functional decomposition is driven by the response to specific environmental stimuli. Rather than natural selection acting to produce general purpose organs, each specific environmental challenge is dealt with by a separate mechanism. All versions of this argument are arguments from analogy, relying on the key transitional premise that minds are a kind of biological system upon which natural selection acts.

The second type of argument makes no appeal to biological considerations whatsoever (although many evolutionary psychologists give these arguments a biological twist). Call this the computational argument, which unfolds as follows: minds are computational problem solving devices; there are specific types of solutions to specific types of problems; and so for minds to be (successful) general problem solving devices, they must consist of collections of specific problem solving devices, i.e. many computational modules. This type of argument is structurally similar to the biological argument (as Carruthers points out). The key idea is that there is no sense to the idea of a general problem solver and that no headway can be made in cognitive science without breaking down problems into their component parts.

The third type of argument involves a generalization of Chomsky’s poverty of the stimulus argument for universal grammar. Many evolutionary psychologists (see, e.g., Tooby & Cosmides 1992) appeal to the idea that there is neither enough time, nor enough available information, for any given human to learn from scratch to successfully solve all of the problems that we face in the world. This first consideration supports the conclusion that the underlying mechanisms we use to solve the relevant problems are innate (for evolutionary psychologists “innate” is usually interchangeable with “product of natural selection” [ 4 ] ). If we invoke this argument across the whole range of problem sets that humans face and solve, we arrive at a huge set of innate mechanisms that subserve our problem solving abilities, which is another way of saying that we have a massively modular mind.

There are numerous responses to the many versions of each of these types of arguments and many take on the massive modularity thesis head on without considering a specific argument for it. I will defer consideration of responses to the first argument type until section 4 below, which focuses on issues of the nature of evolution and natural selection – topics in philosophy of biology.

The second type of argument is one side of a perennial debate in the philosophy of cognitive science. Fodor (2000, 68) takes this argument to rest on the unwarranted assumption that there is no domain-independent criterion of cognitive success, which he thinks requires an argument that evolutionary psychologists do not provide. Samuels (see esp. Samuels 1998) responds to evolutionary psychologists that arguments of this type do not sufficiently discriminate between a conclusion about domain specific processing mechanisms and domain specific knowledge or information. Samuels articulates what he calls the “library model of cognition” in which there is domain specific information or knowledge but domain general processing. The library model of cognition is not massively modular in the relevant sense but type two arguments support it. According to Samuels, evolutionary psychologists need something more than this type of argument to warrant their specific kind of conclusion about massive modularity. Buller (2005) introduces further worries for this type of argument by tackling the assumption that there can be no such thing as a domain general problem solving mechanism. Buller worries that in their attempt to support this claim, evolutionary psychologists fail to adequately characterize a domain general problem solver. For example, they fail to distinguish between a domain general problem solver and a domain specific problem solver that is over generalized. He offers the example of social learning as a domain general mechanism that would produce domain specific solutions to problems. He uses a nice biological analogy to drive this point home: the immune system is a domain general system in that it allows the body to respond to a wide variety of pathogens. While it is true that the immune system produces domain specific responses to pathogens in the form of specific antibodies, the antibodies are produced by one domain general system. These and many other respondents conclude that type two arguments do not adequately support the massive modularity thesis.

Fodor (2000) and Kim Sterelny (2003) provide different responses to type three arguments. Fodor’s response is that poverty of the stimulus type arguments support conclusions about innateness but not modularity and so these arguments can not be used to support the massive modularity thesis. He argues that the domain specificity and encapsulation of a mechanism and its innateness pull apart quite clearly, allowing for “perfectly general learning mechanisms” that are innate and “fully encapsulated mechanisms” that are single stimulus specific and everything in between. Sterelny responds to the generalizing move in type three arguments. He takes language to be the exception rather than the rule in the sense that while the postulation of an innate, domain specific module may be warranted to account for our language abilities, much of our other problem solving behavior can be accounted for without postulating such modules (Sterelny 2003, 200). [ 5 ] Sterelny’s counter requires invoking alternate explanations for our behavioral repertoire. For example, he accounts for folk psychology and folk biology by appealing to environmental factors, some of which are constructed by our forebears, that allow us to perform sophisticated cognitive tasks. If we can account for our success at various complex problem solving tasks, without appealing to modules, then the massive modularity thesis is undercut. Sterelny sharpens his response to massive modularity by adding more detail to his accounts of how many of our uniquely human traits may have evolved (see, e.g., Sterelny 2012). Sterelny introduces his “evolved apprentice” model to account for the evolution of many human traits that many assume require explanation in terms of massive modularity, for example, forming moral judgments. Cecilia Heyes adopts a similar approach to Sterenly in attacking massive modularity. Rather than presenting arguments against massive modularity, she offers alternative explanations of the development of folk psychology that do not rely on the massive modularity thesis (Heyes 2014a; Heyes 2014b).

Heyes and Sterelny not only reject massive modularity but also have little expectation that any modularity theses will bear fruit but there are many critics of the massive modularity thesis who allow for the possibility of some modularity of mind. Such critics of evolutionary psychology do not reject the possibility of any kind of modularity, they just reject the massive modularity thesis. There is considerable debate about the status of the massive modularity thesis and some of this debate centers around the characterization of modules. If modules have all the characteristics that Fodor (1983) first presented, then he may be right that central systems are not modular. Both Carruthers (2006) and Barrett and Kurzban (2006) present modified characterizations of modules, which they argue better serve the massive modularity thesis. There is no agreement on a workable characterization of modules for evolutionary psychology but there is agreement on the somewhat benign thesis that “the language of modularity affords useful conceptual groundwork in which productive debates surrounding cognitive systems can be framed” (Barrett and Kurzban 2006, 644).

Many philosophers have criticized evolutionary psychology. Most of these critics are philosophers of biology who argue that the research tradition suffers from an overly zealous form of adaptationism (Griffiths 1996; Richardson 1996; Grantham & Nichols 1999; Lloyd 1999; Richardson 2007), an untenable reductionism (Dupré 1999, 2001), a “bad empirical bet” about modules (Sterelny 1995; Sterelny & Griffiths 1999; Sterelny 2003), a fast and loose conception of fitness (Lloyd 1999; Lloyd & Feldman 2002); and most of the above and much more (Buller 2005). (See also Downes 2005.) [ 6 ] All of these philosophers share one version or other of Buller’s view: “I am unabashedly enthusiastic about efforts to apply evolutionary theory to human psychology” (2005, x). [ 7 ] But if philosophers of biology are not skeptical of the fundamental idea behind the project, as Buller’s quote indicates, what are they so critical of? What is at stake are differing views about how to best characterize evolution and hence how to generate evolutionary hypotheses and how to test evolutionary hypotheses. For evolutionary psychologists, the most interesting contribution that evolutionary theory makes is the explanation of apparent design in nature or the explanation of the production of complex organs by appeal to natural selection. Evolutionary psychologists generate evolutionary hypotheses by first finding apparent design in the world, say in our psychological make up, and then presenting a selective scenario that would have led to the production of the trait that exhibits apparent design. The hypotheses evolutionary psychologists generate, given that they are usually hypotheses about our psychological capacities, are tested by standard psychological methods. Philosophers of biology challenge evolutionary psychologists on both of these points. I introduce a few examples of criticisms in each of these two areas below and then look at some responses to philosophical criticisms of evolutionary psychology.

Adaptation is the one biological concept that is central to most debates over evolutionary psychology. Every theoretical work on evolutionary psychology presents the research tradition as being primarily focused on psychological adaptations and goes on to give an account of what adaptations are (see, e.g., Tooby & Cosmides 1992; Buss et al. 1998; Simpson & Campbell 2005; Tooby & Cosmides 2005). Much of the philosophical criticism of evolutionary psychology addresses its approach to adaptation or its form of adaptationism. Let us quickly review the basics from the perspective of philosophy of biology.

Here is how Elliott Sober defines an adaptation: “characteristic c is an adaptation for doing task t in a population if and only if members of the population now have c because, ancestrally, there was selection for having c and c conferred a fitness advantage because it performed task t ” (Sober 2000, 85). Sober makes a few further clarifications of the notion of adaptation that are helpful. First, we should distinguish between a trait that is adaptive and a trait that is an adaptation . Any number of traits can be adaptive without those traits being adaptations. A sea turtle’s forelegs are useful for digging in the sand to bury eggs but they are not adaptations for nest building (Sober 2000, 85). Also, traits can be adaptations without being currently adaptive for a given organism. Vestigial organs such as our appendix or vestigial eyes in cave dwelling organisms are examples of such traits (Sterelny and Griffiths 1999). Second, we should distinguish between ontogenic and phylogenetic adaptations (Sober 2000, 86). The adaptations of interest to evolutionary biologists are phylogenetic adaptations, which arise over evolutionary time and impact the fitness of the organism. Ontogenetic adaptations, including any behavior we learn in our lifetimes, can be adaptive to the extent that an organism benefits from them but they are not adaptations in the relevant sense. Finally, adaptation and function are closely related terms. On one of the prominent views of function—the etiological view of functions—adaptation and function are more or less coextensive; to ask for the function of an organ is to ask why it is present. On the Cummins view of functions adaptation and function are not coextensive, as on the Cummins view, to ask what an organ’s function is, is to ask what it does (Sober 2000, 86–87). (See also Sterelny & Griffiths 1999, 220–224.)

Evolutionary psychologists focus on psychological adaptations. One consistent theme in the theoretical work of evolutionary psychologists is that “adaptations, the functional components of organisms, are identified […] by […] evidence of their design: the exquisite match between organism structure and environment” (Hagen 2005, 148). The way in which psychological adaptations are identified is by evolutionary functional analysis, which is a type of reverse engineering. [ 8 ] “Reverse engineering is a process of figuring out the design of a mechanism on the basis of an analysis of the tasks it performs. Evolutionary functional analysis is a form of reverse engineering in that it attempts to reconstruct the mind’s design from an analysis of the problems the mind must have evolved to solve” (Buller 2005, 92). Many philosophers object to evolutionary psychologists’ over attribution of adaptations on the basis of apparent design. Here some are following Gould and Lewontin’s (1979) lead when they worry that accounting for apparent design in nature in terms of adaptation amounts to telling just-so stories but they could just as easily cite Williams (1966), who also cautioned against the over attribution of adaptation as an explanation for biological traits. While it is true that evolutionary functional analysis can lend itself to just-so story telling, this is not the most interesting problem that confronts evolutionary psychology, several other interesting problems have been identified. For example, Elisabeth Lloyd (1999) derives a criticism of evolutionary psychology from Gould and Lewontin’s criticism of sociobiology, emphasizing the point that evolutionary psychologists’ adaptationism leads them to ignore alternative evolutionary processes. Buller takes yet another approach to evolutionary psychologists’ adaptationism. What lies behind Buller’s criticisms of evolutionary psychologists’ adaptationism is a different view than theirs about what is important in evolutionary thinking (Buller 2005). Buller thinks that evolutionary psychologists overemphasize design and that they make the contentious assumption that with respect to the traits they are interested in, evolution is finished, rather than ongoing.

Sober’s definition of adaptation is not constrained only to apply to organs or other traits that exhibit apparent design. Rather, clutch size (in birds), schooling (in fish), leaf arrangement, foraging strategies and all manner of traits can be adaptations (Seger & Stubblefield 1996). Buller argues the more general point that phenotypic plasticity of various types can be an adaptation, because it arises in various organisms as a result of natural selection. [ 9 ] The difference here between Buller (and other philosophers and biologists) and evolutionary psychologists is a difference in the explanatory scope that they attribute to natural selection. For evolutionary psychologists, the hallmark of natural selection is a well functioning organ and for their critics, the results of natural selection can be seen in an enormous range of traits ranging from the specific apparent design features of organs to the most general response profiles in behavior. According to Buller, this latter approach opens up the range of possible evolutionary hypotheses that can account for human behavior. Rather than being restricted to accounting for our behavior in terms of the joint output of many specific modular mechanisms, we can account for our behavior by appealing to selection acting upon many different levels of traits. This difference in emphasis on what is important in evolutionary theory also is at the center of debates between evolutionary psychologists and behavioral ecologists, who argue that behaviors, rather than just the mechanisms that underlie them, can be adaptations (Downes 2001). Further, this difference in emphasis is what leads to the wide range of alternate evolutionary hypotheses that Sterelny (Sterelny 2003) presents to explain human behavior. Given that philosophers like Buller and Sterelny are adaptationists, they are not critical of evolutionary psychologists’ adaptationism. Rather, they are critical of the narrow explanatory scope of the type of adaptationism evolutionary psychologists adopt (see also Downes 2015).

Buller’s criticism that evolutionary psychologists assume that evolution is finished for the traits that they are interested in connects worries about the understanding of evolutionary theory with worries about the testing of evolutionary hypotheses. Here is Tooby & Cosmides’ clear statement of the assumption that Buller is worried about: “evolutionary psychologists primarily explore the design of the universal, evolved psychological and neural architecture that we all share by virtue of being human. Evolutionary psychologists are usually less interested in human characteristics that vary due to genetic differences because they recognize that these differences are unlikely to be evolved adaptations central to human nature. Of the three kinds of characteristics that are found in the design of organisms – adaptations, by-products, and noise – traits caused by genetic variants are predominantly evolutionary noise, with little adaptive significance, while complex adaptations are likely to be universal in the species” (Tooby & Cosmides 2005, 39). This line of thinking also captures evolutionary psychologists’ view of human nature: human nature is our collection of universally shared adaptations. (See Downes & Machery 2013 for more discussion of this and other, contrasting biologically based accounts of human nature.) The problem here is that it is false to assume that adaptations cannot be subject to variation. The underlying problem is the constrained notion of adaptation. Adaptations are traits that arise as a result of natural selection and not traits that exhibit design and are universal in a given species (Seger & Stubblefield 1996). As a result, it is quite consistent to argue, as Buller does, that many human traits may still be under selection and yet reasonably be called adaptations. Finally, philosophers of biology have articulated several different types of adaptationism (see, e.g., Godfrey-Smith 2001; Lewens 2009; Sober 2000). While some of these types of adaptationism can be reasonably seen placing constraints on how evolutionary research is carried out, Godfrey-Smith’s “explanatory adaptationism” is different in character (Godfrey-Smith 2001). Explanatory adaptationism is the view that apparent design is one of the big questions we face in explaining our natural world and natural selection is the big (and only supportable) answer to such a big question. Explanatory adaptationism is often adopted by those who want to distinguish evolutionary thinking from creationism or intelligent design and is the way evolutionary psychologists often couch their work to distinguish it from their colleagues in the broader social sciences. While explanatory adaptationism does serve to distinguish evolutionary psychology from such markedly different approaches to accounting for design in nature, it does not place many clear constraints on the way in which evolutionary explanations should be sought (Downes 2015). So far these are disagreements that are located in differing views about the nature and scope of evolutionary explanation but they have ramifications in the discussion about hypothesis testing.

If the traits of interest to evolutionary psychologists are universally distributed, then we should expect to find them in all humans. This partly explains the stock that evolutionary psychologists put in cross cultural psychological tests (see, e.g., Buss 1990). If we find evidence for the trait in a huge cross section of humans, then this supports our view that the trait is an adaptation —on the assumption that adaptations are organ-like traits that are products of natural selection but not subject to variation. But given the wider scope view of evolution defended by philosophers of biology, this method of testing seems wrong-headed as a test of an evolutionary hypothesis. Certainly such testing can result in the very interesting results that certain preference profiles are widely shared cross culturally but the test does not speak to the evolutionary hypothesis that the preferences are adaptations (Lloyd 1999; Buller 2005).

Another worry that critics have about evolutionary psychologists’ approach to hypothesis testing is that they give insufficient weight to serious alternate hypotheses that fit the relevant data. Buller dedicates several chapters of his book on evolutionary psychology to an examination of hypothesis testing and many of his criticisms center around the introduction of alternate hypotheses that do as good a job, or a better job, of accounting for the data. For example, he argues that the hypothesis of assortative mating by status does a better job of accounting for some of evolutionary psychologists’ mate selection data than their preferred high status preference hypothesis. This debate hangs on how the empirical tests come out. The previous debate is more closely connected to theoretical issues in philosophy of biology.

I said in my introduction that there is a broad consensus among philosophers of science that evolutionary psychology is a deeply flawed enterprise and some philosophers of biology continue to remind us of this sentiment (see, e.g., Dupré 2012). However the relevant consensus is not complete, there are some proponents of evolutionary psychology among philosophers of science. One way of defending evolutionary psychology is to rebut criticism. Edouard Machery and Clark Barrett (2007) do just that in their sharply critical review of Buller’s book. Another way to defend evolutionary psychology is to practice it (at least to the extent that philosophers can, i.e. theoretically). This is what Robert Arp (2006) does in a recent article. I briefly review both responses below.

Machery and Barrett (2007) argue that Buller has no clear critical target as there is nothing to the idea that there is a research tradition of evolutionary psychology that is distinct from the broader enterprise of the evolutionary understanding of human behavior. They argue that theoretical tenets and methods are shared by many in the biology of human behavior. For example, many are adaptationists. But as we saw above, evolutionary psychologists and behavioral ecologists can both call themselves adaptationist but their particular approach to adaptationism dictates the range of hypotheses that they can generate, the range of traits that can be counted as adaptations and impacts upon the way in which hypotheses are tested. Research traditions can share some broad theoretical commitments and yet still be distinct research traditions. Secondly, they argue against Buller’s view that past environments are not stable enough to produce the kind of psychological adaptations that evolutionary psychologists propose. They take this to be a claim that no adaptations can arise from an evolutionary arms race situation, for example, between predators and prey. But again, I think that the disagreement here is over what counts as an adaptation. Buller does not deny that adaptations— traits that arise as a product of natural selection—arise from all kinds of unstable environments. What he denies is that organ-like, special purpose adaptations are the likely result of such evolutionary scenarios.

Arp (2006) defends a hypothesis about a kind of module—scenario visualization—a psychological adaptation that arose in our hominid history in response to the demands of tool making, such as constructing spear throwing devices for hunting. Arp presents his hypothesis in the context of demonstrating the superiority of his approach to evolutionary psychology, which he calls “Narrow Evolutionary Psychology,” over “Broad Evolutionary Psychology,” with respect to accounting for archaeological evidence and facts about our psychology. While Arp’s hypothesis is innovative and interesting, he by no means defends it conclusively. This is partly because his strategy is to compare his hypothesis with archaeologist Steven Mithen’s (1996) non-modular “cognitive fluidity” hypothesis that is proposed to account for the same data. The problem here is that Mithen’s view is only one of the many alternative, evolutionary explanations of human tool making behavior. While Arp’s modular thesis may be superior to Mithen’s, he has not compared it to Sterelny’s (2003; 2012) account of tool making and tool use or to Boyd and Richerson’s (see, e.g., 2005) account and hence not ruled these accounts out as plausible alternatives. As neither of these alternative accounts rely on the postulation of psychological modules, evolutionary psychology is not adequately defended.

Many philosophers who work on moral psychology understand that their topic is empirically constrained. Philosophers take two main approaches to using empirical results in moral psychology. One is to use empirical results (and empirically based theories from psychology) to criticize philosophical accounts of moral psychology (see, e.g., Doris 2002) and one is to generate (and, in the experimental philosophy tradition, to test) hypotheses about our moral psychology (see, e.g., Nichols 2004). For those who think that some (or all) of our moral psychology is based in innate capacities, evolutionary psychology is a good source of empirical results and empirically based theory. One account of the make-up of our moral psychology follows from the massive modularity account of the architecture of the mind. Our moral judgments are a product of domain specific psychological modules that are adaptations and arose in our hominid forebears in response to contingencies in our (mostly) social environments. This position is currently widely discussed by philosophers working in moral psychology. An example of this discussion follows.

Cosmides (see, e.g., 1989) defends a hypothesis in evolutionary psychology that we have a cheater-detection module. [ 10 ] This module is hypothesized to underlie important components of our behavior in moral domains and fits with the massively modular view of our psychology in general. Cosmides (along with Tooby) argues that cheating is a violation of a particular kind of conditional rule that goes along with a social contract. Social exchange is a system of cooperation for mutual benefit and cheaters violate the social contract that governs social exchange (Cosmides & Tooby 2005). The selection pressure for a dedicated cheater-detection module is the presence of cheaters in the social world. The cheater-detection module is an adaptation that arose in response to cheaters. The cheater-detection hypothesis has been the focus of a huge amount of critical discussion. Cosmides and Tooby (2008) defend the idea that cheat detection is modular over hypotheses that more general rules of inference are involved in the kind of reasoning behind cheater detection against critics Ron Mallon (2008) and Fodor (2008). Some criticism of the cheater-detection hypothesis involves rehashing criticisms of massive modularity in general and some treats the hypothesis as a contribution to moral psychology and invokes different considerations. For example, Mallon (2008) worries about the coherence of abandoning a domain general conception of ought in our conception of our moral psychology. This discussion is also ongoing. (See, e.g., Sterelny 2012 for a selection of alternate, non-modular explanations of aspects of our moral psychology.)

Evolutionary psychology is well suited to providing an account of human nature. As noted above (Section 1), evolutionary psychology owes a theoretical debt to human sociobiology. E.O. Wilson took human sociobiology to provide us with an account of human nature (1978). For Wilson human nature is the collection of universal human behavioral repertoires and these behavioral repertoires are best understood as being products of natural selection. Evolutionary psychologists argue that human nature is not a collection of universal human behavioral repertoires but rather the universal psychological mechanisms underlying these behaviors (Tooby & Cosmides 1990). These universal psychological mechanisms are products of natural selection, as we saw in Section 2. above. Tooby and Cosmides put this claim as follows: “the concept of human nature is based on a species-typical collection of complex psychological adaptations” (1990, 17). So, for evolutionary psychologists, “human nature consists of a set of psychological adaptations that are presumed to be universal among, and unique to, human beings” (Buller 2005, 423). Machery’s (2008) nomological account of human nature is based on, and very similar to, the evolutionary psychologists’ account. Machery says that “human nature is the set of properties that humans tend to possess as a result of the evolution of their species” (2008, 323). While Machery’s account appeals to traits that have evolved and are universal (common to all humans), it is not limited to psychological mechanisms. For example, he thinks of bi-pedalism as part of the human nature trait cluster. Machery’s view captures elements of both the sociobiological view and the evolutionary psychology view of human nature. He shares the idea that a trait must be a product of evolution, rather than say social learning or enculturation, with both these accounts.

Some critical challenges to evolutionary psychological accounts of human nature (and the nomological account) derive from similar concerns as those driving criticism of evolutionary psychology in general. In Section 4. we see that discussions of evolutionary psychology are founded on disagreements about how adaptation should be characterized and disagreements about the role of variation in evolution. Some critics charge evolutionary psychologists of assuming that adaptation cannot sustain variation. Buller’s (2005) criticism of evolutionary psychologists’ account of human nature also invokes variation (Here he follows Hull 1986 and Sober 1980). The idea here is that humans, like all organisms, exhibit a great deal of variation, including morphological, physiological, behavioral and cultural variation (see also Amundson 2000). Buller argues that the evolutionary psychology account of human nature either ignores or fails to account for all of this variation (see also Lewens 2015 and Ramsey 2013). Any account that restricts human nature to just those traits we have in common and which also are not subject to change, cannot account for human variation.

Buller’s (2005) criticism of evolutionary psychologists’ notion of human nature (or the nomological account) is based on the idea that we vary across many dimensions and an account of human nature based on fixed, universal traits cannot account for any of this variation. The idea that to account for human nature, we must account for human variation is presented and defended by evolutionary psychologists (see, e.g., Barrett 2015), anthropologists (see e.g. Cashdan 2013) and philosophers (see, e.g., Griffiths 2011 and Ramsey 2013). Barrett agrees with Buller (and others) that evolutionary psychologists have failed to account for human variation in their account of human nature. Rather than seeing this challenge as a knock down of the whole enterprise of accounting for human nature, Barrett sees this as a challenge for an account of human nature. Barrett says “Whatever human nature is, it’s a biological phenomenon with all that implies” (2015, 321). So, human nature is “a big wobbly cloud that is different from the population clouds of squirrels and palm trees. To understand human minds and behaviors, we need to understand the properties of our own cloud, as messy as it might be” (2015, 232). Rather than human nature being a collection of shared fixed universal psychological traits, for Barrett, human nature is the whole human trait cluster, including all of the variation in all of our traits. This approach to human nature is sharply different than the approach defended by either Wilson, Tooby and Cosmides or Machery but is also subject to a number of criticisms. The main thrust of the criticisms is that such a view cannot be explanatory and is instead merely a big list of all the properties that humans have had and can have (see, e.g., Buller 2005; Downes 2016; Futuyma 1998; and Lewens 2015). Discussion over the tension between evolutionary psychologists’ views and the manifest variation in human traits continues in many areas that evolutionary psychologists focus on. Another example of this broader discussion is included in Section 7. below.

Evolutionary psychology is invoked in a wide range of areas of study, for example, in English Literature, Consumer Studies and Law. (See Buss 2005 for discussion of Literature and Law and Saad 2007 for a detailed presentation of evolutionary psychology and consumer studies.) In these contexts, evolutionary psychology is usually introduced as providing resources for practitioners, which will advance the relevant field. Philosophers have responded critically to some of these applications of evolutionary psychology. One concern is that often evolutionary psychology is conflated with evolution or evolutionary theory in general (see, e.g., Leiter & Weisberg 2009 and Downes 2013). The discussion reviewed in Section 4. above, reveals a good deal of disagreement between evolutionary theorists and evolutionary psychologists over the proper account of evolution. Evolutionary psychologists offer to enhance fields such as Law and Consumer Studies by introducing evolutionary ideas but what is in fact offered is a selection of theoretical resources championed only by proponents of a specific approach to evolutionary psychology. For example, Gad Saad (2007) argues that Consumer Studies will profit greatly from the addition of adaptive thinking, i.e. looking for apparent design, and by introducing hypothetical evolved modules to account for consumer behavior. However, this does not appear to be an effort to bring evolutionary theory, broadly construed, to bear on Consumer Studies (Downes 2013). Promoting disputed theoretical ideas is certainly problematic but bigger worries arise when thoroughly discredited work is promoted in the effort to apply evolutionary psychology. Owen Jones (see, e.g., 2000; 2005), who believes that Law will benefit from the application of evolutionary psychology, champions Randy Thornhill and Craig Palmer’s (2000) widely discredited view that rape is an adaptation as exemplary evolutionary work (see de Waal 2000, Coyne & Berry 2000, Coyne 2003, Lloyd 2003, Vickers & Kitcher 2003, and Kimmel 2003). Further, Jones (2000) claims that the critics of Thornhill and Palmer’s work have no credibility as scientists and evolutionary theorists. This claim indicates Jones’ serious disconnect with the wider scientific (and philosophical) literature on evolutionary theory (Leiter & Weisberg 2009).

Aside from monitoring the expansion efforts of evolutionary psychology, there are a number of other areas in which further philosophical work on evolutionary psychology will be fruitful. The examples given above of work in moral psychology barely scratch the surface of this rapidly developing field. There are huge numbers of empirical hypotheses that bear on our conception of our moral psychology that demand philosophical scrutiny. (Hauser 2006 includes a survey of a wide range of such hypotheses.) Also, work on moral psychology and the emotions can be drawn together via work on evolutionary psychology and related fields. Griffiths (1997) directed philosophical attention to evolution and the emotions and this kind of work has been brought into closer contact with moral psychology by Nichols (see, e.g., his 2004). In philosophy of mind there is still much that can be done on the topic of modules. Work on integrating biological and psychological concepts of modules is one avenue that is being pursued and could be fruitfully pursued further (see, e.g., Barrett & Kurzban 2006; Carruthers 2006) and work on connecting biology to psychology via genetics is another promising area (see e.g. Marcus 2004). In philosophy of science, I have no doubt that many more criticisms of evolutionary psychology will be presented but a relatively underdeveloped area of philosophical research is on the relations among all of the various, theoretically different, approaches to the biology of human behavior (but see Downes 2005; Griffiths 2008; and Brown et al. 2011). Evolutionary psychologists present their work alongside the work of behavioral ecologists, developmental psychobiologists and others (see, e.g., Buss 2005; Buss 2007) but do not adequately confront the theoretical difficulties that face an integrated enterprise in the biology of human behavior. Finally, while debate rages between biologically influenced and other social scientists, most philosophers have not paid much attention to potential integration of evolutionary psychology into the broader interdisciplinary study of society and culture (but see Mallon and Stich 2000 on evolutionary psychology and constructivism). In contrast, feminist philosophers have paid attention to this integration issue as well as offered feminist critiques of evolutionary psychology (see Fehr 2012, Meynell 2012 and the entry on feminist philosophy of biology ). Gillian Barker (2015), shares some evolutionarily based criticisms of evolutionary psychology with philosophers of biology discussed in Section 4. but also assesses evolutionary psychology in relation to other social sciences. She also adds a novel critical appraisal of evolutionary psychology. She argues that, as currently practiced, evolutionary psychology is not a fruitful guide to social policy regarding human flourishing.

The publication of Shackleford and Weekes-Shackleford’s (2017) huge collection of articles on issues arising in the evolutionary psychological sciences provides a great resource for philosophers looking for material to fuel critical discussion. Many evolutionary psychologists are aware of the difficulty variation presents for some established approaches in their field. This issue confronts those interested in developing accounts of human nature, as noted above (Section 6.), but also arises when confronting many of the varying human behaviors evolutionary psychologists seek to account for. For example, human aggression varies along many dimensions and confronting and accounting for each of these types of variation is a challenge for many evolutionary psychologists (Downes & Tabery 2017). Given that evolutionary psychology is just one, among many, evolutionarily based approaches to explaining human behavior, the most promising critical discussions of evolutionary psychology should continue to come from work that compares hypotheses drawn from evolutionary psychology with hypotheses drawn from other evolutionary approaches and other approaches in the social sciences more broadly construed. Stephan Linquist (2016) takes this approach to evolutionary psychologists’ work on cultures of honor. Linquist introduces hypotheses from cultural evolution that appear to offer more explanatory bite than those from evolutionary psychology. The broader issue of tension between evolutionary psychology and cultural evolution here will doubtless continue to attract the critical attention of philosophers. (See Lewens 2015 for a nice clear introduction to and discussion of alternative approaches to cultural evolution.)

Interest has re-emerged in the relation(s) between evolutionary psychology and the other social sciences (Buss 2020). Some time ago, John Dupré (1994) diagnosed evolutionary psychology as an exercise in scientific imperialism. Dupré later characterized scientific imperialism as “the tendency for a successful scientific idea to be applied far beyond its original home, and generally with decreasing success the more its application is expanded” (2001, 16). Dupré uses “scientific imperialism” in a pejorative sense and marshals this as a criticism of evolutionary psychology. (See Downes 2017 for further discussion of scientific imperialism and evolutionary psychology.) Buss (2020) does not cite Dupré but might well be responding to him when he proposes that evolutionary psychology constitutes a scientific revolution in Kuhn’s sense. Buss argues that evolutionary psychology is superior to other approaches in psychology, because it has supplanted them (or at least should supplant them) just as Einstein’s physics supplanted Newton’s or just as cognitive psychology supplanted behaviorism. (David Reich [2018] casts ancient DNA research in similarly Kuhnian terms and offers it up as superior to all previous approaches in archaeology.) Buss takes evolutionary psychology to be a meta-theoretical approach best fit for guiding all of psychology. This is one of the many ways in which his appeal to Kuhn is strained, as Buss is not looking back on the supplanting of one theoretical framework by another but rather arguing for the superiority of his approach to others available in psychology. A further, and quite specific way that Buss sees evolutionary psychology as superior to other approaches in psychology (and the social sciences in general, is that evolutionary psychology ignores (or should ignore) proximate explanations. For Buss, evolutionary psychology offers ultimate explanations and these are enough. However, many areas of biology, for example, physiology, trade in proximate explanations and are not likely to be cast aside because of this focus. This implies that there is still a place for proximate explanations in psychology. This brief discussion indicates that the relations between evolutionary psychology and the rest of psychology, and the social sciences, more broadly is a topic well worth pursuing by philosophers of science and Buss’ and Dupré’s accounts present interesting alternate starting points in this endeavor.

Finally, philosophers of science will doubtless continue to check the credentials of evolutionary ideas imported into other areas of philosophy. Philosophers of biology in particular, still voice suspicion if philosophers borrow their evolutionary ideas from evolutionary psychology rather than evolutionary biology. Philip Kitcher (2017) voices this concern with regards to Sharon Street’s (2006) appeals to evolution. Kitcher worries that Street does not rely on “what is known about human evolution” (2017, 187) to provide an account of how her traits of interest may have emerged. As noted above, Machery’s nomological notion of human nature (2008; 2017) is criticized on the grounds that he takes his idea of an evolved trait from evolutionary psychology as opposed to evolutionary biology. Barker (2015) also encourages philosophers, as well as social scientists, to draw from the huge range of theoretical resources evolutionary biologists have to offer, rather than just from those provided by evolutionary psychologists.

• Arp, R., 2006, “The environments of our hominid ancestors, tool-usage and scenario visualization”, Biology and Philosophy , 21: 95–117.
• Barker, G., 2015, Beyond Biofatalism: Human Nature for an Evolving World , New York: Columbia University Press.
• Barrett, H.C., 2015, The Shape of Thought: How mental adaptations evolve , Oxford: Oxford University Press.
• –––, 2012, “Evolutionary Psychology”, in Cambridge Handbook of Cognitive Science , W. Frankish and W.M. Ramsey (eds.), Cambridge: Cambridge University Press, pp. 257–274.
• Barrett, H.C. and R. Kurzban, 2006, “Modularity in Cognition: Framing the debate”, Psychological Review , 113: 628–647.
• Bateson, P. P. G. and P. Martin, 1999, Design for a Life: How behavior and personality develop , London: Jonathan Cape.
• Bjorklund, D. F. and C. Hernandez Blasi, 2005, “Evolutionary Developmental Psychology”, in The Handbook of Evolutionary Psychology , D. Buss (ed.), Hoboken, NJ: Wiley, pp. 828–850.
• Booth, A., 2004, An Evaluation of the Tracking Argument , MA Thesis, University of Utah.
• Brown, G.R., Dickins, T.E., Sear, R. & Laland, K.N., 2011, Evolutionary accounts of human behavioural diversity, Philosophical Transactions of the Royal Society of London B , 366: 313–324.
• Buller, D., 2005, Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature , Cambridge, MA: MIT Press.
• Buss, D., 1990, “International preferences in selecting mates: A study of 37 cultures”, Journal of Cross Cultural Psychology , 21: 5–47.
• –––, 2007, Evolutionary Psychology: The New Science of the Mind , Boston: Allyn and Bacon.
• –––, 2020, “Evolutionary psychology is a scientific revolution”, Evolutionary Behavioral Sciences , 14: 316–323.
• Buss, D. (ed.), 2005, The Handbook of Evolutionary Psychology , Hoboken, NJ: Wiley, Hoboken, NJ.
• Buss, D. M., M. G. Hasleton, et al., 1998, “Adaptations, Exaptations and Spandrels”, American Psychologist , 53: 533–548.
• Cashdan, E., 2013, “What is a human universal? Human behavioral ecology and human nature”, in S.M. Downes and E. Machery (eds.), Arguing About Human Nature , New York: Routledge, pp. 71–80.
• Carruthers, P., 2006, The Architecture of the Mind , Oxford: Clarendon Press.
• Cosmides, L., 1989, “The Logic of Social Exchange: Has natural selection shaped how humans reason? Studies with the Wason Selection Task”, Cognition , 31: 187–276.
• Cosmides, L. and J. Tooby, 2005, “Neurocognitive Adaptations Designed for Social Exchange”, in The Handbook of Evolutionary Psychology , D. Buss (ed.), Hoboken, NJ: Wiley, pp. 584–627.
• –––, 2008, “Can a General Deontic Logic Capture the Facts of Human Moral Reasoning? How the Mind Interprets Social Exchange Rules and Detects Cheaters”, in W. Sinnott-Armstrong (ed.), Moral Psychology: The Evolution of Morality: Adaptations and Innateness , ( Moral Psychology , volume 1), Cambridge, MA: MIT Press, pp. 53–119.
• Cowie, F., 1999, What’s Within? Nativism Reconsidered , New York: Oxford University Press.
• Coyne, J. A., 2003, “Of Vice and Men: A Case Study in Evolutionary Psychology,” in Evolution, Gender, and Rape , C. Brown Travis (ed.), Cambridge MA: MIT Press: 171–190.
• Coyne, J. A. and B. Berry, 2000, “Rape as an Adaptation,” Nature , 404: 121–122.
• Dennett, D. C., 1995, Darwin’s Dangerous Idea , New York: Simon and Schuster.
• de Waal, F., 2000, “Survival of the Rapist,” New York Times , Book Review, April 2, 2000, pp. 24–25.
• Doris, J., 2002, Lack of character: Personality and Moral Behavior , Cambridge: Cambridge University Press.
• Downes, S. M., 2001, “Some recent developments in evolutionary approaches to the study of human behavior and cognition”, Biology and Philosophy , 16: 575–595.
• –––, 2005, “Integrating the Multiple Biological Causes of Human Behavior”, Biology and Philosophy , 20: 177–190.
• –––, 2009, “The Basic Components of the Human Mind Were Not Solidified During the Pleistocene Epoch”, in Contemporary Debates in Philosophy of Biology , F. Ayala and R. Arp (eds.), Oxford: Wiley Blackwell, pp. 243–252.
• –––, 2013, “Evolutionary psychology is not the only productive evolutionary approach to understanding consumer behavior”, Journal of Consumer Psychology , 23: 400–403.
• –––, 2015, “Evolutionary Psychology, Adaptation and Design”, in Handbook of Evolutionary thinking in the Sciences , T. Heams, P. Huneman, G. Lecointre, M. Silberstein (eds.), Dordrecht: Springer, pp. 659–673.
• –––, 2016, “Confronting Variation in the Social and Behavioral Sciences”, Philosophy of Science , 83: 909–920.
• Downes, S.M. and Machery, E., 2013, Arguing About Human Nature , New York: Routledge.
• Downes, S.M. and Tabery, J., 2017, “Variability of Aggression”, in T.K. Shackleford and V. Weekes-Shackleford (eds.), Encyclopedia of Evolutionary Psychological Science , New York: Springer.
• Dupré, J., 1994, “Against Scientific Imperialism”, Philosophy of Science Association Proceedings , 2: 374–381.
• –––, 1998, “Normal People”, Social Research , 65: 221–248.
• –––, 1999, “Review of Steven Pinker, How the Mind Works”, Philosophy of Science , 66: 489–493.
• –––, 2001, Human Nature and the Limits of Science , Oxford: Clarendon Press.
• –––, 2012, “Against Maladaptationism: Or, what’s wrong with evolutionary psychology?”, in J. Dupré, Processes of Life: Essays in Philosophy of Biology , Oxford: Oxford University Press, pp. 245–260.
• Ereshefsky, M., 2007, “Psychological Categories as Homologies: Lessons from Ethology”, Biology and Philosophy , 22: 659–674.
• Faucher, L., 2017, “Biophilosophy of Race”, in D. Livingstone Smith (ed.), How Biology Shapes Philosophy: New Foundations for Naturalism , Cambridge: Cambridge University Press, pp. 247–275.
• Fehr, C., 2012, “Feminist Engagement with Evolutionary Psychology”, Hypatia , 27: 50–72.
• Fodor, J. A., 1983, The Modularity of Mind , Cambridge, MA: MIT Press.
• –––, 2000, The mind doesn’t work that way: the scope and limits of computational psychology , Cambridge, MA: MIT Press.
• –––, 2008, “Comment on Cosmides and Tooby”, in W. Sinnott-Armstrong (ed.), Moral Psychology: The Evolution of Morality: Adaptations and Innateness , ( Moral Psychology , volume 1), Cambridge, MA: MIT Press, pp. 137–141.
• Futuyma, D.J., 1998, Evolutionary Biology , Sunderland, MA: Sinauer.
• Godfrey-Smith, P., 1996, Complexity and the Function of Mind in Nature , Cambridge: Cambridge University Press.
• –––, 2001, “Three Kinds of Adaptationism”, in S.H. Orzack and E. Sober (eds.) Adaptationism and Optimality , Cambridge: Cambridge University Press, pp. 335–357.
• Gould, S. J. and R. Lewontin, 1979, “The spandrels of San Marco and the Panglossian Paradigm: A critique of the adaptationist programme”, Proceedings of the Royal Society London B , 205: 581–598.
• Grantham, T. and S. Nichols, 1999, “Evolutionary Psychology: Ultimate Explanations and Panglossian Predictions”, in V. Hardcastle (ed.), Where Biology Meets Psychology , Cambridge, MA: Mit Press, pp. 47–56.
• Gray, R. D., M. Heaney, et al., 2003, “Evolutionary Psychology and the Challenge of Adaptive Explanation”, in K. Sterelny and J. Fitness (eds.), From Mating to Mentality: Evaluating Evolutionary Psychology , New York: Psychology Press, pp. 247–268.
• Griffiths, P. E., 2011, “Our Plastic Nature”, in S.B. Gissis and E. Jablonka (eds.), Transformations of Lamarckism: From subtle fluids to Molecular Biology , Cambridge, MA: MIT Press, 319–330.
• –––, 2008, “Ethology, Sociobiology and Evolutionary Psychology”, in S. Sarkar and A. Plutynski (eds.), A Companion to Philosophy of Biology , New York: Blackwell, 393–414.
• –––, 2006, “Evolutionary Psychology: History and Current Status”, in S. Sarkar and J. Pfeifer (eds.), Philosophy of Science: An Encyclopedia , New York: Routledge, Volume 1, pp. 263–268.
• –––, 1996, “The Historical Turn in the Study of Adaptation”, British Journal for the Philosophy of Science , 47: 511–532.
• –––, 1997, What Emotions Really Are , Chicago: University of Chicago Press.
• Hagen, E. H., 2005, “Controversial issues in evolutionary psychology”, in The Handbook of Evolutionary Psychology , D. Buss (ed.), Hoboken, NJ: Wiley, pp. 145–174.
• Hauser, M., 2006, Moral Minds: How Nature Designed our universal sense of right and wrong , New York: Harper Collins.
• Hawkes, K., 1990, “Why do men hunt? Benefits for risky choices”, in E. Cashdan (ed.), Risk and Uncertainly in Tribal and Peasant Communities , Boulder, CO: Westview Press, pp. 145–166.
• Heyes, C. M., 2014a, “False belief in infancy: a fresh look”, Developmental Science : 647–659.
• –––, 2014b, “Sub–mentalizing: I’m not really reading your mind”, Perspectives on Psychological Science : 131–143.
• Hirshfield, L. A. and S. A. Gelman, 1994, Mapping the mind: Domain specificity in cognition and culture , New York: Cambridge University Press.
• Hrdy, S., 1999, Mother Nature: Maternal Instincts and How they Shape the Human Species , New York: Ballantine Books.
• Hull, D.L., 1986, “On Human Nature”, PSA (Proceedings of the Biennial Meeting of the Philosophy of Science Association), 2: 3–13.
• Irons, W., 1998, “Adaptively Relevant Environments Versus the Environment of Evolutionary Adaptedness”, Evolutionary Anthropology , 6: 194–294.
• Jeffares, B. and Sterelny, K., 2012, “Evolutionary Psychology”, in The Oxford Handbook of Philosophy of Cognitive Science , E. Margolis, R. Samuels and S.P. Stich (eds.), Oxford: Oxford University Press, pp. 480–502.
• Jones, O.D., 1997, “Evolutionary Analysis in law: An introduction and application to child abuse”, North Carolina Law Review , 75: 1117–1242.
• –––, 2000, “An evolutionary analysis of rape: Reflections on transitions”, Hastings Women’s Law Journal , 11: 151–178.
• –––, 2005, “Evolutionary Psychology and the Law”, The Handbook of Evolutionary Psychology , D.M. Buss (ed.), Hoboken, NJ: Wiley, pp. 953–974.
• Kimmel, M., 2003, “An Unnatural History of Rape,” in Evolution, Gender, and Rape , C. Brown Travis (ed.), Cambridge MA, MIT Press: 221–234.
• Kitcher, P., 2017, “Evolution and Ethical Life”, in D. Livingstone Smith (ed.), How Biology Shapes Philosophy: New Foundations for Naturalism , Cambridge: Cambridge University Press, pp. 184–203.
• Laland, K. N. and G. R. Brown, 2002, Sense and Nonsense: Evolutionary Perspectives on Human Behavior , Oxford: Oxford University Press.
• Laudan, L., 1977, Progress and Its Problems , Berkeley: University of California Press.
• Leiter, B. and Weisberg, M., 2009, “Why Evolutionary Biology is (so far) Irrelevant to Legal Regulation”, Law and Philosophy , 29: 31–74.
• Lewens, T., 2015, Cultural Evolution , Oxford: Oxford University Press.
• –––, 2009, “Seven Types of Adaptationism”, Biology and Philosophy , 24: 161–182.
• Linquist, S., 2016, “Which evolutionary model best explains the culture of honour?”, Biology and Philosophy , 31: 213–235.
• Lewontin, R., 1998, “The evolution of cognition: Questions we will never answer”, in D. Scarborough and S. Sternberg (eds.), Methods, Models, and Conceptual Issues , Cambridge, MA: MIT Press, pp. 107–132.
• Little, D., 1991, Varieties of Social Explanation: An Introduction to the Philosophy of Social Science , Boulder, CO: Westview Press.
• Lloyd, E. A., 1999, “Evolutionary Psychology: The Burdens of Proof”, Biology and Philosophy , 14: 211–233.
• –––, 2003, “Violence against Science: Rape and Evolution,” Evolution, Gender, and Rape , C. Brown Travis (ed.), Cambridge MA, MIT Press: 235–262.
• Lloyd, E. A. and M. W. Feldman, 2002, “Evolutionary Psychology: A View from Evolutionary Biology”, Psychological Inquiry , 13: 150–156.
• Machery, E., 2008, “A Plea for Human Nature”, Philosophical Psychology , 21: 321–329.
• –––, 2017, “Human Nature”, in D. Livingstone Smith (ed.) How Biology Shapes Philosophy: New Foundations for Naturalism , Cambridge University Press, pp. 204–226.
• Machery, E. and H. C. Barrett, 2007, “Review of David Buller Adapting Minds: Evolutionary psychology and the persistent quest for human nature ”, Philosophy of Science , 73: 232–246.
• Mallon, R., 2008, “Ought we to Abandon a Domain General Treatment of ‘Ought’?” in W. Sinnott-Armstrong (ed.), Moral Psychology: The Evolution of Morality: Adaptations and Innateness , ( Moral Psychology , volume 1), Cambridge, MA: MIT Press, pp. 121–130.
• Mallon, R. and S. P. Stich, 2000, “The Odd Couple: The compatibility of social construction and evolutionary psychology”, Philosophy of Science , 67: 133–154.
• Marcus, G., 2004, The Birth of the Mind: How a tiny number of genes creates the complexities of human thought , New York: Basic Books.
• Marr, D., 1983, Vision: A Computational Investigation into the Human Representation and Processing of Visual Information , New York: W.H. Freeman.
• Meynell, L., 2012, “Evolutionary Psychology, Ethology, and Essentialism (Because What They Don’t Know Can Hurt Us)”, Hypatia , 27: 3–27.
• Michel, G. F. and C. L. Moore, 1995, Developmental Psychobiology: An interdisciplinary science , Cambridge: MIT Press.
• Mithen, S., 1996, The Prehistory of the Mind: The cognitive origins of art and science , London: Thames and Hudson.
• Nichols, S., 2004, Sentimental Rules: On the natural foundation of moral judgment , Oxford: Oxford University Press.
• Odenbaugh, J., forthcoming, “Human Nature and the Problem of Variation”.
• Pinker, S., 1997, How the Mind Works , New York: W.W. Norton.
• Ramsey, G., 2013, “Human nature in a post-essentialist world”, Philosophy of Science , 80: 983–993.
• Reich, D., 2018, Who we are and how we got here: Ancient DNA and the new science of the human past , New York: Pantheon Books.
• Rellihan, M., 2012, “Adaptationism and Adaptive Thinking in Evolutionary Psychology”, Philosophical Psychology , 25: 245–277.
• Richardson, R., 1996, “The Prospects for an Evolutionary Psychology: Human Language and Human Reasoning”, Minds and Machines , 6(4): 541–557.
• –––, 2007, Evolutionary Psychology as Maladapted Psychology , Cambridge, MA: MIT Press.
• Richerson, P. J. and R. Boyd, 2005, Not by Genes Alone: How culture transformed human evolution , Chicago: University of Chicago Press.
• Saad, G., 2007, The Evolutionary Bases of Consumption , Mahwah, NJ: Lawrence Erlbaum.
• Samuels, R., 1998, “Evolutionary Psychology and the Massive Modularity Hypothesis”, British Journal for the Philosophy of Science , 49: 575–602.
• –––, 2000, “Massively modular minds: evolutionary psychology and cognitive architecture”, in P. Carruthers and A. Chamberlain (eds.), Evolution and the Human Mind: Modularity, language and meta-cognition , Cambridge: Cambridge University Press, pp. 13–46.
• Samuels, R., S. Stich, et al., 1999a, “Reason and Rationality”, in I. Niiniluoto, M. Sintonen and J. Wolenski (eds.), Handbook of Epistemology , Dordrecht: Kluwer, pp. 131–179.
• Samuels, R., S. Stich, et al., 1999b, “Rethinking Rationality: From Bleak Implications to Darwinian Modules”, in E. Lepore and Z. Pylyshyn (eds.), What is Cognitive Science? Blackwell, Oxford, pp. 74–120.
• Seger, J. and J. W. Stubblefield, 1996, “Optimization and Adaptation”, in M. R. Rose and G. V. Lauder (eds.), Adaptation , San Diego: Academic Press, pp. 93–123.
• Shapiro, L. A. and W. Epstein, 1998, “Evolutionary Theory Meets Cognitive Psychology: A More Selective Perspective”, Mind and Language , 13: 171–194.
• Shackleford, T.K. and Weekes-Shackleford, V. (eds.), 2017, Encyclopedia of Evolutionary Psychological Science , New York: Springer.
• Simpson, J. A. and L. Campbell, 2005, “Methods of evolutionary sciences”, in The Handbook of Evolutionary Psychology , D. Buss (ed.), Hoboken, NJ: Wiley, pp. 119–144.
• Singh, D., 1993, “Adaptive Significance of female physical attractiveness: Role of waist-to-hip ratio”, Journal of Personality and Social Psychology , 65: 293–307.
• Singh, D. and S. Luis, 1995, “Ethnic and gender consensus for the effect of waist to hip ratio on judgments of women’s attractiveness”, Human Nature , 6: 51–65.
• Sinnott-Armstrong, W., (ed.), 2008, Moral Psychology: The Evolution of Morality: Adaptations and Innateness , ( Moral Psychology , Volume 1), Cambridge, Massachusetts: MIT Press.
• Smith, S.E., 2020, “Is evolutionary psychology possible?”, Biological Theory , 15: 39–49.
• Sober, E., 1980, “Evolution, Population Thinking and Essentialism”, Philosophy of Science , 47: 350–383.
• –––, 2000, Philosophy of Biology , Boulder, CO: Westview Press.
• Stanovich, K., 2005, The Robot’s Rebellion: Finding meaning in the age of Darwin , Chicago: University of Chicago Press.
• Sterelny, K., 1995, “The Adapted Mind”, Biology and Philosophy , 10: 365–380.
• –––, 2003, Thought in a Hostile World: The Evolution of Human Cognition , Oxford: Blackwell.
• –––, 2012, The Evolved Apprentice: How evolution made humans unique , Cambridge, MA: MIT Press.
• Sterelny, K. and P. E. Griffiths, 1999, Sex and Death: An Introduction to Philosophy of Biology , Chicago: University of Chicago Press.
• Street, S., 2006, “A Darwinian Dilemma for Realist Theories of Value”, Philosophical Studies , 127: 109–166.
• Thornhill, R. and C.T. Palmer, 2000, A Natural History of Rape: Biological bases of sexual coercion , Cambridge, MA: MIT Press.
• Tooby, J. and L. Cosmides, 1990, “On the universality of human nature and the uniqueness of the individual”, Journal of Personality , 58: 17–67.
• –––, 1992, “The Psychological Foundations of Culture”, in H. Barkow, L. Cosmides and J. Tooby (eds.), The Adapted Mind , New York: Oxford University Press, pp. 19–136.
• –––, 2005, “Conceptual Foundations of Evolutionary Psychology”, in The Handbook of Evolutionary Psychology , D. Buss (ed.), Hoboken, NJ: Wiley, pp. 5–67.
• Vickers, A. L. and P. Kitcher, 2003, “Pop Sociobiology: The Evolutionary Psycholgoy of Sex and Violence,” Evolution, Gender, and Rape , C. Brown Travis (ed.), Cambridge MA: MIT Press, 139–168.
• Williams, G. C., 1966, Adaptation and Natural Selection , Princeton: Princeton University Press.
• Wilson, E.O., 1978, On Human Nature , Cambridge, MA: Harvard University Press.
• Yu, D. W. and G. H. Shepard, 1998, “Is beauty in the eye of the beholder?”, Nature , 396: 321–322.

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Cited Resources

• Buller, D., 2000, “ Evolutionary Psychology ” (a guided tour), in M. Nani and M. Marraffa (eds.), A Field Guide to the Philosophy of Mind .

adaptationism | biology: philosophy of | cognitive science | culture: and cognitive science | emotion | feminist philosophy, interventions: philosophy of biology | -->function --> | game theory: evolutionary | innate/acquired distinction | innateness: and language | language of thought hypothesis | mind: modularity of | moral psychology: empirical approaches | prisoner’s dilemma

Acknowledgments

Thanks to Austin Booth, David Buller, Marc Ereshefsky, Matt Haber, Ron Mallon, Shaun Nichols and the Stanford Encyclopedia referees for helpful comments on drafts of this entry.

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Evolutionary Psychology Research Paper Topics

This page provides a comprehensive list of evolutionary psychology research paper topics , designed to guide students in exploring the depths of human behavior through the lens of evolution. Evolutionary psychology melds principles from psychology, biology, and anthropology to understand how evolutionary processes shape cognitive functions and behaviors that were advantageous for survival and reproduction. The selected topics delve into various aspects such as mating strategies, social behavior, and the evolutionary basis of mental health issues, highlighting the field’s potential to explain both contemporary human behavior and psychological traits. By engaging with these topics, students will not only enhance their academic knowledge but also contribute to a broader understanding of human nature, equipped to address complex psychological questions with evolutionary insights. This resource aims to inspire and facilitate rigorous academic inquiry into how evolutionary past influences present psychological outcomes, fostering a richer understanding of the human condition.

100 Evolutionary Psychology Research Paper Topics

Evolutionary psychology is a dynamic field that integrates insights from psychology, biology, anthropology, and cognitive science to explore the origins and functions of human behavior and cognition. This interdisciplinary approach provides a robust framework for understanding how evolutionary processes influence modern human behavior and psychological traits. Choosing the right evolutionary psychology research paper topics is crucial as these topics can illuminate our understanding of human nature and behavior through an evolutionary lens. By investigating these topics, students can contribute to a deeper comprehension of why humans behave, think, and feel the way they do today, based on adaptations that occurred in response to challenges faced by our ancestors.

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• The principles of natural selection in psychological contexts
• Evolutionary theories of brain development
• The role of genetics in psychological traits
• Comparative psychology: Insights from animal studies
• The adaptationist approach to human psychology
• Evolutionary game theory and human behavior
• Methods and approaches in evolutionary psychology research
• Historical figures and milestones in evolutionary psychology
• Criticisms and controversies in evolutionary psychology
• The future of evolutionary psychology
• The evolution of human mating behaviors
• Sexual selection and its impact on human psychological traits
• Parental investment theories in human development
• The role of attractiveness in mate selection
• Strategies of intrasexual competition
• Mate choice and preference across cultures
• Evolutionary explanations for infidelity and jealousy
• The impact of social status on mating success
• The biology of human sexual orientation
• Gender differences in sexual psychology
• Theories of parental investment and offspring survival
• Evolutionary perspectives on family structure and cohesion
• The role of kin selection in altruistic behaviors within families
• Parent-child relationships from an evolutionary standpoint
• Conflict and cooperation in sibling interactions
• The impact of parental age on reproductive strategies
• Evolutionary views on adoption and step-parenting
• Cross-cultural variations in family dynamics
• The effects of parental behavior on child development
• The evolution of human parenting skills
• The origins of social cooperation and community living
• Evolutionary bases of group dynamics and leadership
• The development of social hierarchies
• Territorial behaviors and their psychological implications
• The role of language in social evolution
• Trust and reputation in evolutionary perspective
• The evolution of conflict and peacemaking
• Social exclusion and its adaptive significance
• Cooperative breeding and communal care in human history
• The evolution of human empathy and moral reasoning
• The biological basis of altruistic behaviors in humans
• Reciprocal altruism and its conditions
• Costly signaling and altruism as a social strategy
• The role of altruism in modern societies
• Evolutionary models of cooperation and fairness
• The genetic and environmental influences on altruistic behavior
• The survival value of altruism in human evolution
• Psychological and physiological benefits of being altruistic
• Altruism in crisis situations: An evolutionary analysis
• The limits and potential selfishness underlying altruistic acts
• The evolution of human intelligence and cognitive functions
• Decision-making processes from an evolutionary perspective
• The adaptiveness of cognitive biases and heuristics
• Memory systems and their evolutionary origins
• The role of perception in survival and reproduction
• Theory of mind and its evolutionary significance
• The evolutionary underpinnings of creativity and innovation
• Cognitive adaptations in response to environmental challenges
• The interplay between cognition and culture in human evolution
• Evolutionary explanations for cognitive disorders
• The adaptive functions of human emotions
• Evolutionary explanations for emotional expressions
• The role of emotions in survival and social interactions
• Fear, anger, joy, and sadness from an evolutionary viewpoint
• The neurobiology of emotions and its evolutionary aspects
• Emotional intelligence as an evolutionary adaptation
• The impact of emotions on decision-making and behavior
• The evolution of emotional disorders
• Cross-cultural studies on emotional perception and expression
• Attachment and love: Evolutionary perspectives
• The evolutionary basis of personality traits
• Personality and survival: An adaptive approach
• The role of personality in mate selection and reproductive success
• Heritability of personality features and evolutionary psychology
• The Big Five personality traits from an evolutionary angle
• Personality disorders: An evolutionary analysis
• The influence of personality on social hierarchy and group dynamics
• Stability and change in personality across the lifespan
• Environmental influences on the development of personality traits
• Personality and health outcomes from an evolutionary perspective
• The evolutionary roots of criminal behavior
• Psychopathy and evolutionary theories of social behavior
• Evolutionary explanations for aggression and violence
• Sexual coercion and evolutionary insights into criminal acts
• The adaptiveness of deceptive and manipulative behaviors
• Evolutionary perspectives on legal decision-making
• The role of evolutionary psychology in criminal profiling
• Evolutionary theories in understanding victimology
• The implications of evolutionary psychology for penal systems
• Moral and ethical considerations in evolutionary forensic psychology
• The evolution of cultural norms and their psychological impacts
• The role of culture in shaping human evolution
• Cultural transmission and its mechanisms from an evolutionary perspective
• Cooperation and competition in cultural groups
• The co-evolution of language and social structures
• The impact of religion on social cohesion and moral behaviors
• Evolutionary approaches to the study of myths and rituals
• Cultural diversity and adaptive strategies in human societies
• The influence of cultural evolution on human cognition
• Future directions in the study of cultural evolution

The exploration of evolutionary psychology research paper topics offers profound insights into the origins and functions of human behavior. These topics span a diverse range of areas, each contributing to a deeper understanding of how evolutionary principles shape our actions, thoughts, and feelings. Students are encouraged to delve into these evolutionary psychology research paper topics, as they hold the potential to not only enrich academic knowledge but also provide practical applications that can inform areas such as therapy, education, policy, and interpersonal relationships. Engaging with these topics is an opportunity to advance our collective understanding of human nature in the context of its evolutionary past.

The Range of Evolutionary Psychology Research Paper Topics

Adaptive Functions of Psychological Traits

The core of evolutionary psychology lies in its attempt to understand psychological traits as adaptations designed to solve recurrent problems faced by our ancestors. This perspective suggests that many aspects of human behavior, including our emotional responses and cognitive abilities, have developed to increase our ancestors’ survival and reproductive success. For instance, fear responses and threat detection mechanisms are crucial adaptive traits that evolved to help early humans avoid predators and other environmental hazards, enhancing their chances of survival and reproduction.

Moreover, reproductive and mating behaviors are central to evolutionary psychology. The field examines various behaviors from mate selection to parental investment, providing a biological and psychological basis for understanding complex social behaviors. For example, evolutionary psychology explores how preferences for certain traits in mates may have evolved to maximize reproductive success and ensure the survival of offspring, highlighting the intricate link between psychological predispositions and reproductive strategies.

Evolutionary Approaches to Mental Health

Evolutionary psychology research paper topics often address the origins of mental health issues by considering them as potential evolutionary mismatches—conditions where the modern environment differs significantly from the ancestral environments in which our psychological traits evolved. This framework can shed light on the prevalence of depression and anxiety in modern societies, suggesting that these disorders may be linked to living conditions that are vastly different from those our evolutionary ancestors faced. For instance, the high rates of depression in highly urbanized and socially fragmented environments can be interpreted through this lens, suggesting a mismatch between our social and environmental needs and what contemporary life offers.

In addition to explaining the origins of mental disorders, evolutionary psychology also considers how our evolutionary past might inform therapeutic approaches. Understanding that certain aspects of modern life may clash with our evolved dispositions can guide the development of treatment plans that better align with our inherent tendencies, potentially improving therapeutic outcomes for a range of psychological disorders.

Cultural Variations and Evolutionary Psychology

Exploring evolutionary psychology research paper topics extends into understanding cultural differences in behaviors and mental processes. This area of study examines how evolutionary pressures may have varied across different environments, leading to cultural diversifications in psychological traits. For instance, risk-taking behaviors might be more prevalent in cultures that historically faced more unpredictable environments, where taking risks could lead to greater rewards.

The interaction between genetic predispositions and cultural expressions also illustrates the adaptive nature of human psychology. Genes provide a framework within which psychological traits develop, but cultural contexts can significantly modulate how these traits are expressed. Additionally, the role of cultural evolution in shaping psychological phenomena suggests that cultural practices themselves may evolve to enhance the fit between human psychology and its environment, further contributing to the diversity of human behavior observed across the globe.

The insights gained from evolutionary psychology research paper topics are invaluable for deepening our understanding of human psychology. By framing psychological traits as products of evolutionary processes, this field provides a comprehensive perspective that integrates biology, psychology, and anthropology. The potential of evolutionary psychology research topics to revolutionize our understanding of human nature is immense, offering ways to enhance psychological interventions and improve mental health outcomes by aligning them more closely with our evolutionary heritage. This approach not only enriches academic knowledge but also has practical implications for developing more effective mental health strategies and fostering healthier societies.

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Evolutionary Psychiatry

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• First Online: 05 September 2024
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• Randolph M. Nesse 10 &
• Dan J. Stein 11  

Evolutionary biology is now the foundation for scientific studies of behavior and emotion, but it is only starting to be applied in psychiatry. It asks new questions that provide a framework for integrating otherwise separate perspectives. The first two questions are about the evolutionary history of a trait and how it gives selective advantages. Answers provide evolutionary explanations of behavior and emotions that synergize with explanations that describe mechanisms and ontogeny. A third question asks why natural selection left us with traits that make us vulnerable to disease. In addition to mutations and environmental exposures, evolutionary psychiatry considers mismatch with modern environments, tradeoffs, and traits that increase gene transmission at the cost of host health. Answers to this question encourage a medical approach to aversive emotions as useful responses. Evolutionary psychiatry is not a method of treatment, but the basic science it brings to psychiatry has practical applications for clinical care, research, and public health that can increase psychiatry’s effectiveness and its recognition as a medical specialty.

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Abed, R. T. (2000). Psychiatry and Darwinism: Time to reconsider? British Journal of Psychiatry, 177 (1), 1–3. https://doi.org/10.1192/bjp.177.1.1

Article   CAS   Google Scholar  

Abed, R. T., & St John-Smith, P. (2016). Evolutionary psychiatry: A new college special interest group. BJPsych Bull, 40 (5), 233–236. https://doi.org/10.1192/pb.bp.115.052407

Article   PubMed   PubMed Central   Google Scholar  

Abed, R. T., & St. John Smith, P. (Eds.). (2022). Evolutionary psychiatry: Current perspectives on evolution and mental health . Cambridge University Press.

Google Scholar  

Abed, R. T., Ayton, A., St John-Smith, P., Swanepoel, A., & Tracy, D. K. (2019). Evolutionary biology: An essential basic science for the training of the next generation of psychiatrists. The British Journal of Psychiatry, 1–3 . https://doi.org/10.1192/bjp.2019.123

Abrams, M. (2020). The new CBT: Clinical evolutionary psychology . Cognella Academic Publishing.

Ahmed, S. H. (2018). “A walk on the wild side” of addiction: The history and significance of animal models. In H. Pickard & S. H. Ahmed (Eds.), Routledge handbook on philosophy and science of addiction (pp. 192–203).

Chapter   Google Scholar  

Akil, H., Brenner, S., Kandel, E., Kendler, K. S., King, M.-C., Scolnick, E., Watson, J. D., & Zoghbi, H. Y. (2010). The future of psychiatric research: Genomes and neural circuits. Science, 327 (5973), 1580–1581.

Akiskal, H. S. (1996). The prevalent clinical spectrum of bipolar disorders: Beyond DSM-IV. Journal of Clinical Psychopharmacology, 16 (2 Suppl 1), 4S–14S.

Article   CAS   PubMed   Google Scholar  

Akiskal, K. K., & Akiskal, H. S. (2005). The theoretical underpinnings of affective temperaments: Implications for evolutionary foundations of bipolar disorder and human nature. Journal of Affective Disorders, 85 (1), 231–239. https://doi.org/10.1016/j.jad.2004.08.002

Article   PubMed   Google Scholar  

Alcock, J. (2001). The triumph of sociobiology . Oxford University Press.

Book   Google Scholar  

Alcock, J. (2013). Animal behavior: An evolutionary approach (17267880, 10th ed.). Sinauer Associates.

Alcock, J., & Sherman, P. (2010). The utility of the proximate-ultimate dichotomy in ethology. Ethology, 96 (1), 58–62. https://doi.org/10.1111/j.1439-0310.1994.tb00881.x

Article   Google Scholar  

Al-Shawaf, L., & Shackelford, T. (2023). The oxford handbook of evolution and the emotions . Oxford University Press.

Al-Shawaf, L., Conroy-Beam, D., Asao, K., & Buss, D. M. (2016). Human emotions: An evolutionary psychological perspective. Emotion Review, 8 (2), 173–186. https://doi.org/10.1177/1754073914565518

Alvergne, A., Jenkinson, C., & Faurie, C. (2016). Evolutionary thinking in medicine: From research to policy and practice . Springer.

Andrews, P. W., & Thomson, J. A. (2009). The bright side of being blue: Depression as an adaptation for analyzing complex problems. Psychological Review, 116 (3), 620–654. https://doi.org/10.1037/a0016242

Apicella, C. L., & Silk, J. B. (2019). The evolution of human cooperation. Current Biology, 29 (11), R447–R450. https://doi.org/10.1016/j.cub.2019.03.036

Archer, J. (2003). The nature of grief: The evolution and psychology of reactions to loss . Routledge.

Asthana, S., Schmidt, S., & Sunyaev, S. (2005). A limited role for balancing selection. Trends in Genetics, 21 (1), 30–32. https://doi.org/10.1016/j.tig.2004.11.001

Austad, S. N., & Hoffman, J. M. (2018). Is antagonistic pleiotropy ubiquitous in aging biology? Evolution, Medicine, and Public Health . https://doi.org/10.1093/emph/eoy033

Axelrod, R. M. (1997). The complexity of cooperation: Agent-based models of competition and collaboration . Princeton University Press.

Barkow, J., Cosmides, L., & Tooby, J. (Eds.). (1992). The adapted mind . Oxford University Press.

Barnes, M. E., Evans, E. M., Hazel, A., Brownell, S. E., & Nesse, R. M. (2017). Teleological reasoning, not acceptance of evolution, impacts students’ ability to learn natural selection. Evolution: Education and Outreach, 10 (1). https://doi.org/10.1186/s12052-017-0070-6

Baron-Cohen, S. (Ed.). (1997). The maladapted mind . Psychology Press.

Baron-Cohen, S. (2000). The cognitive neuroscience of autism: Implications for the evolution of the male brain . The Cognitive Neurosciences.

Bateson, M., Brilot, B., & Nettle, D. (2011). Anxiety: An evolutionary approach. Canadian Journal of Psychiatry. Revue Canadienne de Psychiatrie, 56 (12), 707–715.

Baxter, A. J., Scott, K. M., Ferrari, A. J., Norman, R. E., Vos, T., & Whiteford, H. A. (2014). Challenging the myth of an “epidemic” of common mental disorders: Trends in the global prevalence of anxiety and depression between 1990 and 2010. Depression and Anxiety, 31 (6), 506–516. https://doi.org/10.1002/da.22230

Beck, A. T., & Bredemeier, K. (2016). A unified model of depression integrating clinical, cognitive, biological, and evolutionary perspectives. Clinical Psychological Science, 2167702616628523 . https://doi.org/10.1177/2167702616628523

Beesdo, K., Knappe, S., & Pine, D. S. (2009). Anxiety and anxiety disorders in children and adolescents: Developmental issues and implications for DSM-V. Psychiatric Clinics of North America, 32 (3), 483–524. https://doi.org/10.1016/j.psc.2009.06.002

Belsky, J. (1999). Modern evolutionary theory and patterns of attachment. In J. Cassidy, P. R. Shaver, J. Cassidy, & P. R. Shaver (Eds.), Handbook of attachment: Theory, research, and clinical applications (pp. 141–161). Guilford Press.

Bergstrom, C. T., & Dugatkin, L. A. (2012). Evolution (16949376, 1st ed.). Norton.

Berridge, K. C. (1996). Food reward: Brain substrates of wanting and liking. Neuroscience and Biobehavioral Reviews, 20 (1), 1–25.

Bifulco, A., Brown, G. W., Moran, P., Ball, C., & Campbell, C. (1998). Predicting depression in women: The role of past and present vulnerability. Psychological Medicine, 28 (1), 39–50.

Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology . American Psychological Association.

Bornovalova, M. A., Choate, A. M., Fatimah, H., Petersen, K. J., & Wiernik, B. M. (2020). Appropriate use of bifactor analysis in psychopathology research: Appreciating benefits and limitations. Biological Psychiatry, 88 (1), 18–27. https://doi.org/10.1016/j.biopsych.2020.01.013

Bowlby, J. (1969). Attachment theory, separation anxiety, and mourning, 6 .

Bravo Núñez, M. A., Nuckolls, N. L., & Zanders, S. E. (2018). Genetic villains: Killer meiotic drivers. Trends in Genetics, 34 (6), 424–433. https://doi.org/10.1016/j.tig.2018.02.003

Brown, G. W., Harris, T. O., & Hepworth, C. (1995). Loss, humiliation and entrapment among women developing depression: A patient and non-patient comparison. Psychological Medicine, 25 (1), 7–21.

Brüne, M. (2014). On aims and methods of psychiatry – A reminiscence of 50 years of Tinbergen’s famous questions about the biology of behavior. BMC Psychiatry, 14 (1). https://doi.org/10.1186/s12888-014-0364-y

Brüne, M. (2015). Textbook of evolutionary psychiatry and psychosomatic medicine: The origins of psychopathology . Oxford University Press.

Brüne, M. (2016). Borderline personality disorder: Why ‘fast and furious’? Evolution, Medicine, and Public Health, 2016 (1), 52–66.

Brüne, M., & Schiefenhövel, W. (2019). The Oxford handbook of evolutionary medicine . Oxford University Press.

Brüne, M., Belsky, J., FaBrega, H., FeierMan, J. R., Gilbert, P., Glantz, K., PoliMeni, J., Price, J. S., Sanjuan, J., Sullivan, R., Troisi, A., & Wilson, D. R. (2012). The crisis of psychiatry – Insights and prospects from evolutionary theory. World Psychiatry, 11 (1), 55–57. https://doi.org/10.1016/j.wpsyc.2012.01.009

Buller, D. J. (2005). Evolutionary psychology: The emperor’s new paradigm. Trends in Cognitive Sciences, 9 (6), 277–283. https://doi.org/10.1016/j.tics.2005.04.003

Burt, A., & Trivers, R. L. (2006). Genes in conflict: The biology of selfish genetic elements . Belknap Press of Harvard University Press.

Buss, D. M. (1995). Evolutionary psychology: A new paradigm for psychological science. Psychological Inquiry, 6 (1), 1–30.

Buss, D. M. (2000). The evolution of happiness. American Psychologist, 55 (1), 15–23.

Buss, D. M. (2015). The handbook of evolutionary psychology (Vol. 1). John Wiley & Sons.

Buss, D. M., Shackelford, T. K., Kirkpatrick, L. A., Choe, J. C., Lim, H. K., Hasegawa, M., Hasegawa, T., & Bennett, K. (1999). Jealousy and the nature of beliefs about infidelity: Tests of competing hypotheses about sex differences in the United States, Korea, and Japan. Personal Relationships, 6 (1), 125–150.

Byars, S. G., Stearns, S. C., & Boomsma, J. J. (2014). Opposite risk patterns for autism and schizophrenia are associated with normal variation in birth size: Phenotypic support for hypothesized diametric gene-dosage effects. Proceedings of the Royal Society B, 281 (1794), 20140604. https://doi.org/10.1098/rspb.2014.0604

Carew, T. J., Hawkins, R. D., & Kandel, E. R. (1983). Differential classical conditioning of a defensive withdrawal reflex in Aplysia californica. Science, 219 (4583), 397–400.

Carver, C. S., & Scheier, M. F. (1990). Origins and functions of positive and negative affect: A control-process view. Psychological Review, 97 (1), 19–35. https://doi.org/10.1037/0033-295X.97.1.19

Caspi, A., Houts, R. M., Belsky, D. W., Goldman-Mellor, S. J., Harrington, H., Israel, S., Meier, M. H., Ramrakha, S., Shalev, I., Poulton, R., & Moffitt, T. E. (2014). The p factor: One general psychopathology factor in the structure of psychiatric disorders? Clinical Psychological Science, 2 (2), 119–137. https://doi.org/10.1177/2167702613497473

Charnov, E. L. (1976). Optimal foraging: The marginal value theorem. Theoretical and Population Biology, 9 , 129–136.

Chisholm, J. S. (1996). The evolutionary ecology of attachment organization. Hu Nat, 7 (1), 1–37. https://doi.org/10.1007/BF02733488

Cohen, S., Kessler, R. C., & Gordon, L. U. (1997). Measuring stress: A guide for health and social scientists . Oxford University Press.

Confer, J. C., Easton, J. A., Fleischman, D. S., Goetz, C. D., Lewis, D. M. G., Perilloux, C., & Buss, D. M. (2010). Evolutionary psychology: Controversies, questions, prospects, and limitations. American Psychologist, 65 (2), 110–126. https://doi.org/10.1037/a0018413

Cory, G. A. (2002). MacLean’s evolutionary neuroscience, the CSN model and Hamilton’s rule: Some developmental, clinical, and social policy implications. Brain and Mind, 3 (1), 151–181. https://doi.org/10.1023/A:1016514009636

Cosmides, L., & Tooby, J. (1987). From evolution to behavior: Evolutionary psychology as the missing link. In J. Dupre (Ed.), The latest on the best: Essays on evolution and optimality . MIT Press.

Cozolino, L. J. (2014). The neuroscience of human relationships: Attachment and the developing social brain (2nd ed.). W.W. Norton & Company.

Crespi, B. J. (2000). The evolution of maladaptation. Heredity, 84 (6), 623–629. https://doi.org/10.1046/j.1365-2540.2000.00746.x

Crespi, B. J. (2009). Evolutionary genetics of affective disorders. In C. Pariante, R. M. Nesse, D. Nutt, L. Wolpert, C. Pariante, R. M. Nesse, D. Nutt, & L. Wolpert (Eds.), Understanding depression (pp. 37–54). http://oxfordmedicine.com/view/10.1093/med/9780199533077.001.0001/med-9780199533077-chapter-004

Crespi, B. J. (2010). The origins and evolution of genetic disease risk in modern humans: Evolution of human disease risk. Annals of the New York Academy of Sciences, 1206 (1), 80–109. https://doi.org/10.1111/j.1749-6632.2010.05707.x

Crespi, B. J. (2018). Autism, psychosis, and genomic imprinting: Recent discoveries and conundrums. Current Opinion in Behavioral Sciences, 25 , 1–7. https://doi.org/10.1016/j.cobeha.2018.05.008

Crespi, B. J., & Badcock, C. (2008). Psychosis and autism as diametrical disorders of the social brain. Behavioral and Brain Sciences, 31 (03). https://doi.org/10.1017/S0140525X08004214

Crespi, B. J., & Dinsdale, N. (2019). Autism and psychosis as diametrical disorders of embodiment. Evolution, Medicine, and Public Health, eoz021 . https://doi.org/10.1093/emph/eoz021

Crespi, B. J., & Go, M. C. (2015). Diametrical diseases reflect evolutionary-genetic tradeoffs: Evidence from psychiatry, neurology, rheumatology, oncology and immunology. Evolution, Medicine, and Public Health, 2015 (1), 216–253.

Crespi, B. J., Foster, K., & Úbeda, F. (2014). First principles of Hamiltonian medicine. Philosophical Transactions of the Royal Society B: Biological Sciences, 369 (1642). https://doi.org/10.1098/rstb.2013.0366

Crouch, D. J. M., & Bodmer, W. F. (2020). Polygenic inheritance, GWAS, polygenic risk scores, and the search for functional variants. Proceedings of the National Academy of Sciences, 117 (32), 18924–18933. https://doi.org/10.1073/pnas.2005634117

Crow, T. J. (1997). Is schizophrenia the price that Homo sapiens pays for language? Schizophrenia Research, 28 (2–3), 127–141.

Curtis, D. (2018). Polygenic risk score for schizophrenia is more strongly associated with ancestry than with schizophrenia. Psychiatric Genetics, 28 (5), 85–89. https://doi.org/10.1097/YPG.0000000000000206

Daly, M., & Wilson, M. (1981). Abuse and neglect of children in evolutionary perspective . Chiron Press.

Daly, M., & Wilson, M. (1983). Sex, evolution, and behavior (2nd ed.). Willard Grant Press.

Daly, M., & Wilson, M. (1988a). Evolutionary social psychology and family homicide. Science, 242 (4878), 519–524.

Daly, M., & Wilson, M. (1988b). The Darwinian psychology of discriminative parental solicitude. Nebraska Symposium on Motivation, 35 , 91–144.

Darwin, C. (1998). The expression of the emotions in man and animals . Oxford University Press.

Darwin, C., & Darwin, F. (1887). The life and letters of Charles Darwin, including an autobiographical chapter (3rd ed.). J. Murray.

Dawkins, R. (1976). The selfish gene . Oxford University Press.

Del Giudice, M. (2016). The life history model of psychopathology explains the structure of psychiatric disorders and the emergence of the p factor: A simulation study. Clinical Psychological Science, 4 (2), 299–311.

Del Giudice, M., & Crespi, B. J. (2018). Basic functional trade-offs in cognition: An integrative framework. Cognition, 179 , 56–70. https://doi.org/10.1016/j.cognition.2018.06.008

Dettwyler, K. A. (1995). A time to wean: The hominid blueprint for the natural age of weaning in modern human populations. In P. Stuart-Macadam & K. A. Dettwyler (Eds.), Breastfeeding: Biocultural perspectives (pp. 39–73). Aldine de Gruyter.

Diener, E., Lucas, R. E., & Scollon, C. N. (2006). Beyond the hedonic treadmill: Revising the adaptation theory of well-being. American Psychologist, 61 (4), 305–314. https://doi.org/10.1037/0003-066X.61.4.305

Douglas, M. (1966). Purity and danger: An analysis of concepts of pollution and taboo . Routledge and Keegan Paul.

Doyle, C., Swain, W. A., Swain Ewald, H. A., & Ewald, P. W. (2019). Inflammation, infection and depression: An evolutionary perspective. Evolutionary Human Sciences, 1 , e14. https://doi.org/10.1017/ehs.2019.15

Driscoll, C. (2005). Killing babies: Hrdy on the evolution of infanticide. Biology and Philosophy, 20 (2), 271–289. https://doi.org/10.1007/s10539-004-0680-6

Dudley, R. (2002). Fermenting fruit and the historical ecology of ethanol ingestion: Is alcoholism in modern humans an evolutionary hangover? Addiction, 97 (4), 381–388.

Dugatkin, L. A. (1997). Cooperation among animals: An evolutionary perspective . Oxford University Press.

Dunbar, R. I. M. (2020). Evolution: What everyone needs to know® (2nd ed.). Oxford University Press.

Dunbar, R. I. M. (1993). Coevolution of neocortical size, group size and language in humans. Behavioral and Brain Sciences, 16 (04), 681–694.

Edenberg, H. J. (2007). The genetics of alcohol. Metabolism, 30 (1), 9.

Ekman, P. (2003). Emotions inside out: 130 years after Darwin’s the expression of the emotions in man and animals . NYAS.

Ekman, P., & Friesen, W. V. (1986). A new pan-cultural facial expression of emotion. Motivation and Emotion, 10 (2), 159–168.

Ellis, B. J., & Del Giudice, M. (2014). Beyond allostatic load: Rethinking the role of stress in regulating human development. Development and Psychopathology, 26 (01), 1–20.

Erickson, M. T. (1993). Rethinking Oedipus: An evolutionary perspective of incest avoidance. American Journal of Psychiatry, 150 (3), 411–416. https://doi.org/10.1176/ajp.150.3.411

Ewald, P. W. (2018). Darwinian medicine: Evolutionary approaches to disease. In H. Callan (Ed.), The international encyclopedia of anthropology (pp. 1–9). John Wiley & Sons, Ltd. https://doi.org/10.1002/9781118924396.wbiea1862

Finlay-Jones, R., & Brown, G. (1981). Types of stressful life events and the onset of anxiety and depression. Psychological Medicine, 11 , 803–815.

First, M. B., & Wakefield, J. C. (2013). Diagnostic criteria as dysfunction indicators: Bridging the chasm between the definition of mental disorder and diagnostic criteria for specific disorders. The Canadian Journal of Psychiatry, 58 (12), 663–669. https://doi.org/10.1177/070674371305801203

Fraley, R. C., Brumbaugh, C. C., & Marks, M. J. (2005). The evolution and function of adult attachment: A comparative and phylogenetic analysis. Journal of Personality and Social Psychology, 89 (5), 731.

Fredrickson, B. L. (2004). The broaden-and-build theory of positive emotions. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 359 (1449), 1367–1378. https://doi.org/10.1098/rstb.2004.1512

Fried, E. I., Nesse, R. M., Zivin, K., Guille, C., & Sen, S. (2014). Depression is more than the sum score of its parts: Individual DSM symptoms have different risk factors. Psychological Medicine, 44 (10), 2067–2076. https://doi.org/10.1017/S0033291713002900

Galbally, M., Lewis, A. J., & IJzendoorn, M. van, & Permezel, M. (2011). The role of oxytocin in mother-infant relations: A systematic review of human studies. Harvard Review of Psychiatry, 19 (1), 1–14. https://doi.org/10.3109/10673229.2011.549771

Gazzaniga, M. S. (1992). Nature’s mind: The biological roots of thinking, emotions, sexuality, language, and intelligence . Basic Books.

Gelles, R. J., & Lancaster, J. B. (1987). Child abuse and neglect: Biosocial dimensions . Aldine De Gruyter.

Ghaemi, S. N. (2010). The rise and fall of the biopsychosocial model: Reconciling art and science in psychiatry . Johns Hopkins University Press.

Gilbert, P. (1992). Depression: The evolution of powerlessness . Guilford.

Gilbert, P. (1995). Biopsychosocial approaches and evolutionary theory as aids to integration in clinical psychology and psychotherapy. Clinical Psychology & Psychotherapy, 2 (3), 135–156.

Gilbert, P. (2006). Evolution and depression: Issues and implications. Psychological Medicine, 36 (03), 287–297.

Gilbert, P., & Bailey, K. G. (2000). Genes on the couch: Explorations in evolutionary psychotherapy . Taylor & Francis.

Gluckman, P. D., & Hanson, M. (2006). Mismatch: Why our world no longer fits our bodies . Oxford University Press.

Gluckman, P. D., Beedle, A., & Hanson, M. (2009). Principles of evolutionary medicine . Oxford University Press.

Gluckman, P. D., Hanson, M. A., & Low, F. M. (2019). Evolutionary and developmental mismatches are consequences of adaptive developmental plasticity in humans and have implications for later disease risk. Philosophical Transactions of the Royal Society B: Biological Sciences, 374 (1770), 20180109. https://doi.org/10.1098/rstb.2018.0109

Gratten, J., Wray, N. R., Keller, M. C., & Visscher, P. M. (2014). Large-scale genomics unveils the genetic architecture of psychiatric disorders. Nature Neuroscience, 17 (6), 782–790.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Gratten, J., Wray, N. R., Peyrot, W. J., McGrath, J. J., Visscher, P. M., & Goddard, M. E. (2016). Risk of psychiatric illness from advanced paternal age is not predominantly from de novo mutations. Nature Genetics, 48 (7), 718–724. https://doi.org/10.1038/ng.3577

Greenberg, D. M., Warrier, V., Allison, C., & Baron-Cohen, S. (2018). Testing the empathizing–systemizing theory of sex differences and the extreme male brain theory of autism in half a million people. Proceedings of the National Academy of Sciences, 115 (48), 12152–12157. https://doi.org/10.1073/pnas.1811032115

Greenwood, T. A. (2016). Positive traits in the bipolar spectrum: The space between madness and genius. Molecular Neuropsychiatry, 2 (4), 198–212. https://doi.org/10.1159/000452416

Griffiths, P. E. (1997). What emotions really are: The problem of psychological categories . University of Chicago Press.

Griffiths, P. E., & Matthewson, J. (2018). Evolution, dysfunction, and disease: A reappraisal. The British Journal for the Philosophy of Science, 69 (2), 301–327.

Gruber, J. (2011). Can feeling too good be bad? Positive emotion persistence (PEP) in bipolar disorder. Current Directions in Psychological Science, 20 (4), 217–221. https://doi.org/10.1177/0963721411414632

Grunspan, D. Z., Nesse, R. M., Barnes, M. E., & Brownell, S. E. (2018). Core principles of evolutionary medicine. Evolution, Medicine, and Public Health, 2018 (1), 13–23. https://doi.org/10.1093/emph/eox025

Grunspan, D. Z., Moeller, K. T., Nesse, R. M., & Brownell, S. E. (2019). The state of evolutionary medicine in undergraduate education. Evolution, Medicine, and Public Health, 2019 (1), 82–92. https://doi.org/10.1093/emph/eoz012

Gulsuner, S., Stein, D. J., Susser, E. S., Sibeko, G., Pretorius, A., Walsh, T., Majara, L., Mndini, M. M., Mqulwana, S. G., Ntola, O. A., Casadei, S., Ngqengelele, L. L., Korchina, V., van der Merwe, C., Malan, M., Fader, K. M., Feng, M., Willoughby, E., Muzny, D., et al. (2020). Genetics of schizophrenia in the South African Xhosa. Science, 367 (6477), 569–573. https://doi.org/10.1126/science.aay8833

Hagen, E. H. (2011). Evolutionary theories of depression: A critical review. The Canadian Journal of Psychiatry, 56 (12), 716–726.

Hagen, E. H., Roulette, C. J., & Sullivan, R. J. (2013). Explaining human recreational use of ‘pesticides’: The neurotoxin regulation model of substance use vs. the hijack model and implications for age and sex differences in drug consumption. Frontiers in Psychiatry, 4 . https://doi.org/10.3389/fpsyt.2013.00142

Haig, D. (2020). From Darwin to Derrida: Selfish genes, social selves, and the meanings of life . MIT Press.

Hamilton, W. D. (1964). The genetical evolution of social behavior I, and II. Journal of Theoretical Biology, 7 , 1–52.

Hammen, C. (2005). Stress and depression. Annual Review of Clinical Psychology, 1 (1), 293–319. https://doi.org/10.1146/annurev.clinpsy.1.102803.143938

Hammerstein, P. (2003). Genetic and cultural evolution of cooperation . MIT Press.

Hardy, C. L., & Van Vugt, M. (2006). Nice guys finish first: The competitive altruism hypothesis. Personality and Social Psychology Bulletin, 32 (10), 1402–1413. https://doi.org/10.1177/0146167206291006

Harlow, H. F., & Harlow, M. K. (1962). Social deprivation in monkeys. Scientific American, 207 , 136–146.

Harris, C. R. (2003). Factors associated with jealousy over real and imagined infidelity: An examination of the social-cognitive and evolutionary psychology perspectives. Psychology of Women Quarterly, 27 (4), 319–329. https://doi.org/10.1111/1471-6402.00112

Hart, B. L. (1988). Biological basis of the behavior of sick animals. Neuroscience & Biobehavioral Reviews, 12 (2), 123–137.

Haselton, M. G., & Buss, D. M. (2000). Error management theory: A new perspective on biases in cross-sex mind reading. Journal of Personality and Social Psychology, 78 (1), 81.

Haselton, M. G., & Ketelaar, T. (2006). Irrational emotions or emotional wisdom? The evolutionary psychology of affect and social behavior. Affect in Social Thinking and Behavior, 8 , 21.

Heckhausen, J., & Schultz, R. (1995). A life-span theory of control. Psychological Review, 102 (2), 284–304.

Hill, E. M., & Newlin, D. B. (2002). Evolutionary approaches to addiction. Addiction, 97 (4), 375–379.

Hrdy, S. B. (2009). Mothers and others: The evolutionary origins of mutual understanding . Harvard University Press. https://books.google.com/books?hl=en&lr=&id=dsiksDFQPDsC&oi=fnd&pg=PA1&dq=sarah+hrdy&ots=81GpaWr7WI&sig=gQqWvcZ9B_jd6zgHBGVwEMDCIOI

Hutcherson, C. A., Montaser-Kouhsari, L., Woodward, J., & Rangel, A. (2015). Emotional and utilitarian appraisals of moral dilemmas are encoded in separate areas and integrated in ventromedial prefrontal cortex. Journal of Neuroscience, 35 (36), 12593–12605. https://doi.org/10.1523/JNEUROSCI.3402-14.2015

Hyman, S. E. (2018). The daunting polygenicity of mental illness: Making a new map. Philosophical Transactions of the Royal Society B: Biological Sciences, 373 (1742), 20170031. https://doi.org/10.1098/rstb.2017.0031

Insel, T. R. (2000). Toward a neurobiology of attachment. Review of General Psychology, 4 (2), 176–185.

Insel, T. R., & Quirion, R. (2005). Psychiatry as a clinical neuroscience discipline. JAMA, 294 (17), 2221–2224. https://doi.org/10.1001/jama.294.17.2221

Insel, T. R., & Young, L. J. (2001). The neurobiology of attachment. Nature Reviews Neuroscience, 2 (2), 129–136.

Insel, T. R., Cuthbert, B., Garvey, M., Heinssen, R., Pine, D. S., Quinn, K., Sanislow, C., & Wang, P. (2010). Research domain criteria (RDoC): Toward a new classification framework for research on mental disorders. The American Journal of Psychiatry, 167 (7), 748–751. https://doi.org/10.1176/appi.ajp.2010.09091379

Jasienska, G., Ellison, P. T., Galbarczyk, A., Jasienski, M., Kalemba-Drozdz, M., Kapiszewska, M., Nenko, I., Thune, I., & Ziomkiewicz, A. (2015). Apolipoprotein E (ApoE) polymorphism is related to differences in potential fertility in women: A case of antagonistic pleiotropy? Proceedings of the Royal Society B: Biological Sciences, 282 (1803), 20142395. https://doi.org/10.1098/rspb.2014.2395

Article   CAS   PubMed Central   Google Scholar  

Kaas, J. H. (2020). Evolutionary neuroscience . Academic Press.

Kandel, E. R., Schwartz, J. H., & Jessell, T. M. (2000). Principles of neural science (11769631, 4th ed.). McGraw-Hill, Health Professions Division.

Keller, M. C. (2018). Evolutionary perspectives on genetic and environmental risk factors for psychiatric disorders. Annual Review of Clinical Psychology, 14 (1), 471–493. https://doi.org/10.1146/annurev-clinpsy-050817-084854

Keller, M. C., & Miller, G. (2006). Resolving the paradox of common, harmful, heritable mental disorders: Which evolutionary genetic models work best? Behavioral and Brain Sciences, 29 (4), 385–404. https://doi.org/10.1017/S0140525X06009095

Keller, M. C., & Nesse, R. M. (2006). The evolutionary significance of depressive symptoms: Different adverse situations lead to different depressive symptom patterns. Journal of Personality and Social Psychology, 91 (2), 316–330. https://doi.org/10.1037/0022-3514.91.2.316

Kendler, K. S. (2012). The dappled nature of causes of psychiatric illness: Replacing the organic–functional/hardware–software dichotomy with empirically based pluralism. Molecular Psychiatry, 17 (4), 377–388. https://doi.org/10.1038/mp.2011.182

Kendler, K. S. (2013). What psychiatric genetics has taught us about the nature of psychiatric illness and what is left to learn. Molecular Psychiatry, 18 (10), 1058–1066. https://doi.org/10.1038/mp.2013.50

Kendler, K. S., Eaves, L. J., Walters, E. E., Neale, M. C., Heath, A. C., & Kessler, R. C. (1996). The identification and validation of distinct depressive syndromes in a population-based sample of female twins. Archives of General Psychiatry, 53 (5), 391–399.

Kennair, L. E. O. (2007). Fear and fitness revisited. Journal of Evolutionary Psychology, 5 (1), 105–117.

Kennair, L. E. O., Kleppestø, T. H., Larsen, S. M., & Jørgensen, B. E. G. (2017). Depression: Is rumination really adaptive? In T. K. Shackelford & V. Zeigler-Hill (Eds.), The evolution of psychopathology (pp. 73–92). Springer International Publishing. https://doi.org/10.1007/978-3-319-60576-0_3

Kennair, L. E. O., Kleppestø, T. H., Jørgensen, B. E. G., & Larsen, S. M. (2018). Evolutionary clinical psychology. In T. K. Shackelford, V. A. Weekes-Shackelford, T. K. Shackelford, & V. A. Weekes-Shackelford (Eds.), Encyclopedia of evolutionary psychological science (pp. 1–14). http://link.springer.com/10.1007/978-3-319-16999-6_688-1

Kessler, R. C. (1997). The effects of stressful life events on depression. Annual Review of Psychology, 48 (1), 191–214.

Kessler, R. C., Aguilar-Gaxiola, S., Alonso, J., Chatterji, S., Lee, S., Ormel, J., Üstün, T. B., & Wang, P. S. (2009). The global burden of mental disorders: An update from the WHO World Mental Health (WMH) surveys. Epidemiologia e Psichiatria Sociale, 18 (01), 23–33.

Klinger, E. (1975). Consequences of commitment to and disengagement from incentives. Psychological Review, 82 , 1–25.

Konner, M. (1983). The tangled wing: Biological constraints on the human spirit . Penguin.

Krebs, J. R., & Davies, N. B. (1993). An introduction to behavioural ecology (3rd ed.). Blackwell Scientific Publications.

Kringelbach, M. L., & Berridge, K. C. (2016). Neuroscience of reward, motivation, and drive. In Recent developments in neuroscience research on human motivation . Emerald Group Publishing Limited.

Kruger, D. J., & Nesse, R. M. (2006). An evolutionary life-history framework for understanding sex differences in human mortality rates. Human Nature, 17 (1), 74–97. https://doi.org/10.1007/s12110-006-1021-z

Lakoff, G., & Johnson, M. (2010). Philosophy in the flesh: The embodied mind and its challenge to Western thought (Nachdr.) . Basic Books.

Lazarus, R. S. (1993). From psychological stress to the emotions: A history of changing outlooks. Annual Review of Psychology, 44 (1), 1–22.

LeDoux, J. E. (2012a). Evolution of human emotion. Progress in Brain Research, 195 , 431–442. https://doi.org/10.1016/B978-0-444-53860-4.00021-0

LeDoux, J. E. (2012b). Rethinking the emotional brain. Neuron, 73 (4), 653–676. https://doi.org/10.1016/j.neuron.2012.02.004

LeDoux, J. E., & Pine, D. S. (2016). Using neuroscience to help understand fear and anxiety: A two-system framework. American Journal of Psychiatry, 173 (11), 1083–1093. https://doi.org/10.1176/appi.ajp.2016.16030353

Lewin, K. (1951). Problems of research in social psychology. In D. Cartwright (Ed.), Field theory in social science: Selected theoretical papers (pp. 155–169). Harper & Row.

Lewis, D. M., Al-Shawaf, L., Conroy-Beam, D., Asao, K., & Buss, D. M. (2017). Evolutionary psychology: A how-to guide. American Psychologist, 72 (4), 353.

Li, M. D., & Burmeister, M. (2009). New insights into the genetics of addiction. Nature Reviews Genetics, 10 (4), 225–231. https://doi.org/10.1038/nrg2536

Lieberman, D., Tooby, J., & Cosmides, L. (2003). Does morality have a biological basis? An empirical test of the factors governing moral sentiments relating to incest. Proceedings of the Royal Society B: Biological, 270 (1517), 819–826.

Lionetti, F., Aron, A., Aron, E. N., Burns, G. L., Jagiellowicz, J., & Pluess, M. (2018). Dandelions, tulips and orchids: Evidence for the existence of low-sensitive, medium-sensitive and high-sensitive individuals. Translational Psychiatry, 8 (1), 24. https://doi.org/10.1038/s41398-017-0090-6

Lipowsky, Z. J. (1989). Psychiatry: Mindless or brainless, both or neither. Canadian Journal of Psychiatry., 34 , 249–254.

Luhrmann, T. (2000). Of two minds: The growing disorder in American psychiatry . Knopf.

Lynch, M., Ackerman, M. S., Gout, J.-F., Long, H., Sung, W., Thomas, W. K., & Foster, P. L. (2016). Genetic drift, selection and the evolution of the mutation rate. Nature Reviews Genetics, 17 (11), 704–714. https://doi.org/10.1038/nrg.2016.104

Mace, R., Jordan, F., & Holden, C. (2003). Testing evolutionary hypotheses about human biological adaptation using cross-cultural comparison. Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology, 136 (1), 85–94.

MacLean, P. D. (1985). Evolutionary psychiatry and the triune brain. Psychological Medicine, 15 (2), 219–221. https://doi.org/10.1017/S0033291700023485

MacLean, P. D. (1990). The triune brain in evolution . Plenum.

Main, M. (2000). The organized categories of infant, child, and adult attachment: Flexible vs. inflexible attention under attachment-related stress. Journal of the American Psychoanalytic Association, 48 (4), 1055–1096; discussion 1175–1187.

Maj, M., Stein, D. J., Parker, G., Zimmerman, M., Fava, G. A., De Hert, M., Demyttenaere, K., McIntyre, R. S., Widiger, T., & Wittchen, H. (2020). The clinical characterization of the adult patient with depression aimed at personalization of management. World Psychiatry, 19 (3), 269–293. https://doi.org/10.1002/wps.20771

Marais, L., Daniels, W., Brand, L., Viljoen, F., Hugo, C., & Stein, D. J. (2006). Psychopharmacology of maternal separation anxiety in vervet monkeys. Metabolic Brain Disease, 21 (2–3), 191–200. https://doi.org/10.1007/s11011-006-9011-8

Marks, I. M., & Nesse, R. M. (1994). Fear and fitness: An evolutionary analysis of anxiety disorders. Ethology and Sociobiology, 15 , 247–261.

Martin, A. R., Daly, M. J., Robinson, E. B., Hyman, S. E., & Neale, B. M. (2019). Predicting polygenic risk of psychiatric disorders. Biological Psychiatry, 86 (2), 97–109. https://doi.org/10.1016/j.biopsych.2018.12.015

Matthewson, J., & Griffiths, P. E. (2017). Biological criteria of disease: Four ways of going wrong. The Journal of Medicine and Philosophy: A Forum for Bioethics and Philosophy of Medicine, 42 (4), 447–466. https://doi.org/10.1093/jmp/jhx004

Mayr, E. (1961). Cause and effect in biology: Kinds of causes, predictability, and teleology are viewed by a practicing biologist. Science, 134 (3489), 1501–1506.

Mayr, E. (1993). Proximate and ultimate causations. Biology and Philosophy, 8 (1), 93–94. https://doi.org/10.1007/BF00868508

McGuire, M. T. (1976). An ethological approach to psychiatric disorders and treatment systems. McLean Hospital Journal, 1 , 21–33.

McGuire, M. T., & Fairbanks, L. A. (1977). Ethological psychiatry: Psychopathology in the context of evolutionary biology (M. Greenblatt, Ed.). Grune and Stratton.

McGuire, M. T., & Troisi, A. (1987). Physiological regulation-dysregulation and psychiatric disorders. Ethology and Sociobiology, 8 , 9s–12s.

McGuire, M. T., & Troisi, A. (2006). Steps toward an evolutionary-based theory of psychotherapy–I. Clinical Neuropsychiatry, 3 , 162–169.

McGuire, M. T., Essock-Vitale, S. M., & Polsky, R. H. (1981). Psychiatric disorders in the context of evolutionary biology: An ethological model of behavioral changes associated with psychiatric disorders. Journal of Nervous and Mental Disease, 169 (11), 687–704.

McGuire, M. T., Marks, I. M., Nesse, R. M., & Troisi, A. (1992). Evolutionary biology: A basic science for psychiatry. Acta Psychiatrica Scandinavica, 86 , 89–96.

McNamara, J. M., & Trimmer, P. C. (2019). Sequential choices using signal detection theory can reverse classical predictions. Behavioral Ecology, 30 (1), 16–19. https://doi.org/10.1093/beheco/ary132

Meacham, F., & Bergstrom, C. T. (2016). Adaptive behavior can produce maladaptive anxiety due to individual differences in experience. Evolution, Medicine, and Public Health, 2016 (1), 270–285. https://doi.org/10.1093/emph/eow024

Mikulincer, M., & Shaver, P. R. (2012). An attachment perspective on psychopathology. World Psychiatry, 11 , 11–15.

Miller, A. H., & Raison, C. L. (2016). The role of inflammation in depression: From evolutionary imperative to modern treatment target. Nature Reviews Immunology, 16 (1), 22–34. https://doi.org/10.1038/nri.2015.5

Miller, G. E., & Wrosch, C. (2007). You’ve Gotta know when to Fold’Em goal disengagement and systemic inflammation in adolescence. Psychological Science, 18 (9), 773–777.

Murphy, D., & Stich, S. (2011). Evolutionary psychology and the classification of mental disorders. Collected Papers, Volume 1: Mind and Language, 1972–2010, 1 , 270.

Murphy, D., Stich, S., Carruthers, P., & Chamberlain, A. (2000). Darwin in the madhouse: Evolutionary psychology and the classification of mental disorders. In Evolution and the human mind: Modularity, language and meta-cognition (pp. 62–92).

Muscatell, K. A., Slavich, G. M., Monroe, S. M., & Gotlib, I. H. (2009). Stressful life events, chronic difficulties, and the symptoms of clinical depression. The Journal of Nervous and Mental Disease, 197 (3), 154.

Natterson-Horowitz, B. (2019). Tinbergean approach to clinical medicine. In Integrating evolutionary biology into medical education: For maternal and child healthcare students, clinicians, and scientists (pp. 187–197). Oxford University Press.

Natterson-Horowitz, B., & Bowers, K. (2019). Wildhood: The epic journey from adolescence to adulthood in humans and other animals . Scribe Publications.

Nesic, M. J., Stojkovic, B., & Maric, N. P. (2019). On the origin of schizophrenia: Testing evolutionary theories in the post-genomic era. Psychiatry and Clinical Neurosciences, 73 (12), 723–730. https://doi.org/10.1111/pcn.12933

Nesse, R. M. (1984). An evolutionary perspective on psychiatry. Comprehensive Psychiatry, 25 (6), 575–580.

Nesse, R. M. (1990). Evolutionary explanations of emotions. Human Nature, 1 (3), 261–289.

Nesse, R. M. (1999). Proximate and evolutionary studies of anxiety, stress and depression: Synergy at the interface. Neuroscience & Biobehavioral Reviews, 23 (7), 895–903.

Nesse, R. M. (2000). Is depression an adaptation? Archives of General Psychiatry, 57 (1), 14–20.

Nesse, R. M. (2004a). Cliff-edged fitness functions and the persistence of schizophrenia (commentary). Behavioral and Brain Sciences, 27 (6), 862–863.

Nesse, R. M. (2004b). Natural selection and the elusiveness of happiness. Philosophical Transactions of the Royal Society B: Biological Sciences, 359 (1449), 1333–1347. https://doi.org/10.1098/rstb.2004.1511

Nesse, R. M. (2005a). An evolutionary framework for understanding grief. In D. Carr, R. Nesse, & C. B. Wortman (Eds.), Late life widowhood in the United States (pp. 195–226). Springer.

Nesse, R. M. (2005b). Twelve crucial points about emotions, evolution and mental disorders. Psychology Review, 11 (4), 12–14.

Nesse, R. M. (2005c). Natural selection and the regulation of defenses. Evolution and Human Behavior, 26 (1), 88–105. https://doi.org/10.1016/j.evolhumbehav.2004.08.002

Nesse, R. M. (2005d). Maladaptation and natural selection. Quarterly Review of Biology, 80 (1), 62–70.

Nesse, R. M. (2006). The smoke detector principle: Natural selection and the regulation of defensive responses. Annals of the New York Academy of Sciences, 935 (1), 75–85. https://doi.org/10.1111/j.1749-6632.2001.tb03472.x

Nesse, R. M. (2007). Runaway social selection for displays of partner value and altruism. Biological Theory, 2 (2), 143–155.

Nesse, R. M. (2009). Explaining depression: Neuroscience is not enough, evolution is essential. In C. M. Pariente, R. M. Nesse, D. J. Nutt, L. Wolpert, C. M. Pariente, R. M. Nesse, D. J. Nutt, & L. Wolpert (Eds.), Understanding depression: A translational approach (pp. 17–35). Oxford University Press.

Nesse, R. M. (2011). Ten questions for evolutionary studies of disease vulnerability. Evolutionary Applications, 4 (2), 264–277. https://doi.org/10.1111/j.1752-4571.2010.00181.x

Nesse, R. M. (2013). Tinbergen’s four questions, organized: A response to Bateson and Laland. Trends in Ecology & Evolution, 28 (12), 681–682.

Nesse, R. M. (2019a). Good reasons for bad feelings: Insights from the frontier of evolutionary psychiatry . Dutton Books.

Nesse, R. M. (2019b). Tinbergen’s four questions: Two proximate, two evolutionary. Evolution, Medicine, and Public Health , (1), 2–2. https://doi.org/10.1093/emph/eoy035

Nesse, R. M. (2020). Tacit creationism in emotions research. Emotion Researcher, ISRE’s Sourcebook for Research on Emotion and Affect . http://emotionresearcher.com/tacit-creationism-in-emotion-research/

Nesse, R. M. (2023). Evolutionary psychiatry: Foundations, progress and challenges. World Psychiatry, 22 (2), 177–202. https://doi.org/10.1002/wps.21072

Nesse, R. M., & Berridge, K. C. (1997). Psychoactive drug use in evolutionary perspective. Science, 278 (5335), 63–66. https://doi.org/10.1126/science.278.5335.63

Nesse, R. M., & Schulkin, J. (2019). An evolutionary medicine perspective on pain and its disorders. Philosophical Transactions of the Royal Society B: Biological Sciences, 374 (1785), 20190288. https://doi.org/10.1098/rstb.2019.0288

Nesse, R. M., & Stein, D. J. (2012). Towards a genuinely medical model for psychiatric nosology. BMC Medicine, 10 (1), 5. https://doi.org/10.1186/1741-7015-10-5

Nesse, R. M., & Stein, D. J. (2019). How evolutionary psychiatry can advance psychopharmacology. Dialogues in Clinical Neuroscience, 21 (2), 167–175.

Nesse, R. M., & Williams, G. C. (1994). Why we get sick: The new science of Darwinian medicine . Vintage Books.

Nettle, D. (2004). Evolutionary origins of depression: A review and reformulation. Journal of Affective Disorders, 81 (2), 91–102. https://doi.org/10.1016/j.jad.2003.08.009

Nettle, D. (2011). Normality, disorder and evolved function: The case of depression. Maladapting Minds: Philosophy, Psychiatry, and Evolutionary Theory , 198–215.

Ohlsson, H., & Kendler, K. S. (2020). Applying causal inference methods in psychiatric epidemiology: A review. JAMA Psychiatry, 77 (6), 637. https://doi.org/10.1001/jamapsychiatry.2019.3758

Olds, J. (1958). Self-stimulation of the brain: Its use to study local effects of hunger, sex, and drugs. Science, 127 (3294), 315–324.

Painter, D. T., Lessios-Damerow, J., & Laubichler, M. (2021). The evolution of evolutionary medicine. SSRN Electronic Journal . https://doi.org/10.2139/ssrn.3775609

Panksepp, J. (1998). Affective neuroscience: The foundations of human and animal emotions . Oxford University Press.

Pardiñas, A. F., Holmans, P., Pocklington, A. J., Escott-Price, V., Ripke, S., Carrera, N., Legge, S. E., Bishop, S., Cameron, D., Hamshere, M. L., Han, J., Hubbard, L., Lynham, A., Mantripragada, K., Rees, E., MacCabe, J. H., McCarroll, S. A., Baune, B. T., Breen, G., et al. (2018). Common schizophrenia alleles are enriched in mutation-intolerant genes and in regions under strong background selection. Nature Genetics, 1 . https://doi.org/10.1038/s41588-018-0059-2

Patel, V., Saxena, S., Lund, C., et al. (2018). The Lancet Commission on global mental health and sustainable development. Lancet, 392 , 1553–1598.

Peng, Q., Wilhelmsen, K. C., & Ehlers, C. L. (2021). Common genetic substrates of alcohol and substance use disorder severity revealed by pleiotropy detection against GWAS catalog in two populations. Addiction Biology, 26 (1), e12877. https://doi.org/10.1111/adb.12877

Perlman, R. L. (2005). Why disease persists: An evolutionary nosology. Medicine, Health Care and Philosophy, 8 (3), 343–350. https://doi.org/10.1007/s11019-005-2655-z

Perlman, R. L. (2013). Evolution and medicine . Oxford University Press.

Pfaff, D., Tabansky, I., & Haubensak, W. (2019). Tinbergen’s challenge for the neuroscience of behavior. Proceedings of the National Academy of Sciences , 201903589. https://doi.org/10.1073/pnas.1903589116

Pine, D. S. (2007). Research review: A neuroscience framework for pediatric anxiety disorders. Journal of Child Psychology and Psychiatry, 48 (7), 631–648. https://doi.org/10.1111/j.1469-7610.2007.01751.x

Plutchik, R. (1970). Emotions, evolution, and adaptive processes. In Feelings and emotions (pp. 3–24). Elsevier. https://doi.org/10.1016/B978-0-12-063550-4.50007-3

Polimanti, R., & Gelernter, J. (2018). ADH1B: From alcoholism, natural selection, and cancer to the human phenome. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 177 (2), 113–125. https://doi.org/10.1002/ajmg.b.32523

Power, R. A., Kyaga, S., Uher, R., MacCabe, J. H., Långström, N., Landen, M., McGuffin, P., Lewis, C. M., Lichtenstein, P., & Svensson, A. C. (2013). Fecundity of patients with schizophrenia, autism, bipolar disorder, depression, anorexia nervosa, or substance abuse vs their unaffected siblings. JAMA Psychiatry, 70 (1), 22. https://doi.org/10.1001/jamapsychiatry.2013.268

Price, J. S. (1967). The dominance hierarchy and the evolution of mental illness. The Lancet, 290 (7509), 243–246.

Price, J. S. (2013). An evolutionary perspective on anxiety and anxiety disorders. New Insights into Anxiety Disorders, 1 .

Price, J. S., Sloman, L., Gardner, R., Gilbert, P., & Rohde, P. (1994). The social competition hypothesis of depression. The British Journal of Psychiatry, 164 (3), 309–315.

Raison, C. L., & Miller, A. H. (2013). The evolutionary significance of depression in Pathogen Host Defense (PATHOS-D). Molecular Psychiatry, 18 (1), 15–37.

Rantala, M. J., & Marcinkowska, U. M. (2011). The role of sexual imprinting and the Westermarck effect in mate choice in humans. Behavioral Ecology and Sociobiology, 65 (5), 859–873.

Rantala, M. J., Luoto, S., Krams, I., & Karlsson, H. (2018). Depression subtyping based on evolutionary psychiatry: Proximate mechanisms and ultimate functions. Brain, Behavior, and Immunity, 69 , 603–617. https://doi.org/10.1016/j.bbi.2017.10.012

Ressler, K. J. (2020). Translating across circuits and genetics toward progress in fear- and anxiety-related disorders. American Journal of Psychiatry, 177 (3), 214–222. https://doi.org/10.1176/appi.ajp.2020.20010055

Richerson, P., Baldini, R., Bell, A., Demps, K., Frost, K., Hillis, V., Mathew, S., Newton, E., Narr, N., Newson, L., et al. (2015). Cultural group selection plays an essential role in explaining human cooperation: A sketch of the evidence. Behavioral and Brain Sciences , 1–71.

Riso, L. P., du Toit, P. L., Stein, D. J., & Young, J. E. (Eds.). (2007). Cognitive schemas and core beliefs in psychological problems: A scientist-practitioner guide (1st ed.). American Psychological Association.

Rottenberg, J. (2014). The depths: The evolutionary origins of the depression epidemic.

Roved, J., Westerdahl, H., & Hasselquist, D. (2017). Sex differences in immune responses: Hormonal effects, antagonistic selection, and evolutionary consequences. Hormones and Behavior, 88 , 95–105. https://doi.org/10.1016/j.yhbeh.2016.11.017

Rowell, T. E., Din, N. A., & Omar, A. (2009). The social development of baboons in their first three months. Journal of Zoology, 155 (4), 461–483. https://doi.org/10.1111/j.1469-7998.1968.tb03063.x

Rozin, P., Haidt, J., & McCauley, C. R. (2008). Disgust. In M. Lewis, J. M. Haviland-Jones, & L. F. Barrett (Eds.), Handbook of emotions (3rd ed., pp. 757–776). Guilford Press.

Ruse, M. (2017). Social Darwinism. In On human nature (pp. 651–659). Elsevier. https://doi.org/10.1016/B978-0-12-420190-3.00038-7

Schulkin, J., & Power, M. (2019). Integrating evolutionary biology into medical education: For maternal and child healthcare students, clinicians, and scientists . Oxford University Press.

Seligman, M. E., & Csikszentmihalyi, M. (2014). Positive psychology: An introduction. In Flow and the foundations of positive psychology (pp. 279–298). Springer.

Shackelford, T. K., & Zeigler-Hill, V. (Eds.). (2017). The evolution of psychopathology . Springer International Publishing. https://doi.org/10.1007/978-3-319-60576-0

Shattuck, E. C., & Muehlenbein, M. P. (2015). Human sickness behavior: Ultimate and proximate explanations. American Journal of Physical Anthropology, 157 (1), 1–18. https://doi.org/10.1002/ajpa.22698

Shepher, J. (1971). Mate selection among second generation kibbutz adolescents and adults: Incest avoidance and negative imprinting. Archives of Sexual Behavior, 1 (4), 293–307.

Shepherd, S. V. (Ed.). (2017). The Wiley handbook of evolutionary neuroscience . Wiley Blackwell.

Sieff, D. F. (2019). The death mother as nature’s shadow: Infanticide, abandonment, and the collective unconscious. Psychological Perspectives, 62 (1), 15–34. https://doi.org/10.1080/00332925.2019.1564513

Siegert, R. J., & Ward, T. (2002). Clinical psychology and evolutionary psychology: Toward a dialogue. Review of General Psychology, 6 (3), 235–259. https://doi.org/10.1037/1089-2680.6.3.235

Simpson, J. A. (1999). Attachment theory in modern evolutionary perspective. In J. Cassidy & P. R. Shaver (Eds.), Handbook of attachment: Theory, research, and clinical applications (pp. 115–140). Guilford Press.

Skuse, D. H. (2000). Imprinting, the X-chromosome, and the male brain: Explaining sex differences in the liability to autism. Pediatric Research, 47 (1), 9–9. https://doi.org/10.1203/00006450-200001000-00006

Sloman, L. (2008). A new comprehensive evolutionary model of depression and anxiety. Journal of Affective Disorders, 106 (3), 219–228.

Sloman, L., & Price, J. S. (1987). Losing behavior (yielding subroutine) and human depression: Proximate and selective mechanisms. Ethology & Sociobiology, 8 (3, Suppl), 99–109.

Smith, J. M., & Szathmáry, E. (1995). The major transitions of evolution . Freeman.

Smoller, J. W., Andreassen, O. A., Edenberg, H. J., Faraone, S. V., Glatt, S. J., & Kendler, K. S. (2019). Psychiatric genetics and the structure of psychopathology. Molecular Psychiatry, 24 (3), 409–420. https://doi.org/10.1038/s41380-017-0010-4

Soper, C. A. (2019). Adaptation to the suicidal niche. Evolutionary Psychological Science . https://doi.org/10.1007/s40806-019-00202-3

St John-Smith, P., McQueen, D., Edwards, L., & Schifano, F. (2013). Classical and novel psychoactive substances: Rethinking drug misuse from an evolutionary psychiatric perspective. Human Psychopharmacology: Clinical and Experimental, 28 (4), 394–401. https://doi.org/10.1002/hup.2303

Stearns, S. C., & Medzhitov, R. (2016). Evolutionary medicine . Sinauer Associates, Inc., Publishers.

Stein, D. J. (2006a). Advances in understanding the anxiety disorders: The cognitive-affective neuroscience of “false alarms”. Annals of Clinical Psychiatry, 18 (3), 173–182. https://doi.org/10.1080/10401230600801192

Stein, D. J. (2006b). Evolutionary psychiatry: Integrating evolutionary theory and modern psychiatry. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 30 (5), 765. https://doi.org/10.1016/j.pnpbp.2006.01.002

Stein, D. J. (2011). Philosophy of psychopharmacology: Smart pills, happy pills and pepp pills . Cambridge University Press.

Stein, D. J. (2013). What is a mental disorder? A perspective from cognitive-affective science. The Canadian Journal of Psychiatry, 58 (12), 656–662. https://doi.org/10.1177/070674371305801202

Stein, D. J., & Bouwer, C. (1997). A neuro-evolutionary approach to the anxiety disorders. Journal of Anxiety Disorders, 11 (4), 409–429.

Stein, D. J., & Vythilingum, B. (2007). Social anxiety disorder: Psychobiological and evolutionary underpinnings. CNS Spectrums, 12 (11), 806–809. https://doi.org/10.1017/S1092852900015534

Stein, D. J., Liu, Y., Shapira, N. A., & Goodman, W. K. (2001). The psychobiology of obsessive-compulsive disorder: How important is the role of disgust? Current Psychiatry Reports, 3 (4), 281–287. https://doi.org/10.1007/s11920-001-0020-3

Stein, D. J., Seedat, S., Iversen, A., & Wessely, S. (2007). Post-traumatic stress disorder: Medicine and politics. The Lancet, 369 (9556), 139–144. https://doi.org/10.1016/S0140-6736(07)60075-0

Stein, D. J., Lund, C., & Nesse, R. M. (2013). Classification systems in psychiatry: Diagnosis and global mental health in the era of DSM-5 and ICD-11. Current Opinion in Psychiatry, 26 (5), 493–497. https://doi.org/10.1097/YCO.0b013e3283642dfd

Stein, D. J., Billieux, J., Bowden-Jones, H., Grant, J. E., Fineberg, N., Higuchi, S., Hao, W., Mann, K., Matsunaga, H., Potenza, M. N., Rumpf, H. M., Veale, D., Ray, R., Saunders, J. B., Reed, G. M., & Poznyak, V. (2018). Balancing validity, utility and public health considerations in disorders due to addictive behaviours. World Psychiatry, 17 (3), 363–364. https://doi.org/10.1002/wps.20570

Strathearn, L., Fonagy, P., Amico, J., & Montague, P. R. (2009). Adult attachment predicts maternal brain and oxytocin response to infant cues. Neuropsychopharmacology, 34 (13), 2655–2666. https://doi.org/10.1038/npp.2009.103

Striedter, G. F. (2020). Chapter 1 – A history of ideas in evolutionary neuroscience. In J. H. Kaas (Ed.), Evolutionary neuroscience (2nd ed., pp. 3–16). Academic Press. https://doi.org/10.1016/B978-0-12-820584-6.00001-5

Sullivan, R. J., & Hagen, E. H. (2002). Psychotropic substance-seeking: Evolutionary pathology or adaptation? Addiction, 97 (4), 389–400. https://doi.org/10.1046/j.1360-0443.2002.00024.x

Susser, E., & Patel, V. (2014). Psychiatric epidemiology and global mental health: Joining forces. International Journal of Epidemiology, 43 (2), 287–293. https://doi.org/10.1093/ije/dyu053

Syme, K. L., & Hagen, E. H. (2020). Mental health is biological health: Why tackling “diseases of the mind” is an imperative for biological anthropology in the 21st century. American Journal of Physical Anthropology, 171 (S70), 87–117. https://doi.org/10.1002/ajpa.23965

Szymanska, M., Schneider, M., Chateau-Smith, C., Nezelof, S., & Vulliez-Coady, L. (2017). Psychophysiological effects of oxytocin on parent–child interactions: A literature review on oxytocin and parent–child interactions. Psychiatry and Clinical Neurosciences, 71 (10), 690–705. https://doi.org/10.1111/pcn.12544

Takahashi, M., Singh, R. S., & Stone, J. (2017). A theory for the origin of human menopause. Frontiers in Genetics, 7 . https://doi.org/10.3389/fgene.2016.00222

Takeno, K. (2016). Stress-induced flowering: The third category of flowering response. Journal of Experimental Botany, 67 (17), 4925–4934. https://doi.org/10.1093/jxb/erw272

Teicher, M. H., & Samson, J. A. (2016). Annual research review: Enduring neurobiological effects of childhood abuse and neglect. Journal of Child Psychology and Psychiatry, 57 (3), 241–266. https://doi.org/10.1111/jcpp.12507

Tinbergen, N. (1963). On the aims and methods of ethology. Zeitschrift für Tierpsychologie, 20 , 410–463.

Tooby, J., & Cosmides, L. (1990). The past explains the present: Emotional adaptations and the structure of ancestral environments. Ethology and Sociobiology, 11 (4–5), 375–424.

Trivers, R. L. (1971). The evolution of reciprocal altruism. Quarterly Review of Biology, 46 , 35–57.

Trivers, R. L. (1974). Parent-offspring conflict. Integrative and Comparative Biology, 14 (1), 249–264.

Troisi, A., & McGuire, M. T. (2002). Darwinian psychiatry and the concept of mental disorder. Neuroendocrinology Letters, 23 (Suppl 4), 31–38.

PubMed   Google Scholar  

Trumble, B. C., Stieglitz, J., Blackwell, A. D., Allayee, H., Beheim, B., Finch, C. E., Gurven, M., & Kaplan, H. (2017). Apolipoprotein E4 is associated with improved cognitive function in Amazonian forager-horticulturalists with a high parasite burden. The FASEB Journal, 31 (4), 1508–1515. https://doi.org/10.1096/fj.201601084R

Turke, P. W. (2008). Williams’s theory of the evolution of senescence: Still useful at fifty. The Quarterly Review of Biology, 83 (3), 243–256. https://doi.org/10.1086/590509

Uricchio, L. H. (2019). Evolutionary perspectives on polygenic selection, missing heritability, and GWAS. Human Genetics . https://doi.org/10.1007/s00439-019-02040-6

van Dongen, J., & Boomsma, D. I. (2013). The evolutionary paradox and the missing heritability of schizophrenia. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 162 (2), 122–136. https://doi.org/10.1002/ajmg.b.32135

van Staaden, M. J., Hall, F. S., & Huber, R. (2018). The deep evolutionary roots of ‘addiction’. Journal of Mental Health, 6 .

Vanderveldt, A., Oliveira, L., & Green, L. (2016). Delay discounting: Pigeon, rat, human – Does it matter? Journal of Experimental Psychology. Animal Learning and Cognition, 42 (2), 141–162. https://doi.org/10.1037/xan0000097

Wakefield, J. C. (1992). The concept of mental disorder: On the boundary between biological facts and social values. American Psychologist, 47 (3), 373.

Wakefield, J. C. (2007). The concept of mental disorder: Diagnostic implications of the harmful dysfunction analysis. World Psychiatry, 8 .

Weinberger, D. R., & Radulescu, E. (2016). Finding the elusive psychiatric “lesion” with 21st-century neuroanatomy: A note of caution. The American Journal of Psychiatry, 173 (1), 27–33. https://doi.org/10.1176/appi.ajp.2015.15060753

Wenegrat, B. (1984). Sociobiology and mental disorder: A new view . Addison-Wesley Publishing Company.

Westermarck, E. (1922). The history of human marriage (Vol. 2). Allerton Book Company.

Westneat, D. F., & Fox, C. W. (2010). Evolutionary behavioral ecology . Oxford University Press.

Whiteford, H. A., Degenhardt, L., Rehm, J., Baxter, A. J., Ferrari, A. J., Erskine, H. E., Charlson, F. J., Norman, R. E., Flaxman, A. D., Johns, N., Burstein, R., Murray, C. J., & Vos, T. (2013). Global burden of disease attributable to mental and substance use disorders: Findings from the Global Burden of Disease Study 2010. The Lancet, 382 (9904), 1575–1586. https://doi.org/10.1016/S0140-6736(13)61611-6

Wierzbicka, A. (2010). The “history of emotions” and the future of emotion research. Emotion Review, 2 (3), 269–273.

Willers, L. E. W. G., Vulink, N. C., Denys, D., & Stein, D. J. (2013). The origin of anxiety disorders—an evolutionary approach. In D. S. Baldwin & B. E. Leonard (Eds.), Modern trends in psychiatry (vol. 29, pp. 16–23). S. Karger AG. https://doi.org/10.1159/000351919

Williams, G. C. (1966). Adaptation and natural selection: A critique of some current evolutionary thought . Princeton University Press.

Williams, G. C., & Nesse, R. M. (1991). The dawn of Darwinian medicine. The Quarterly Review of Biology, 66 (1), 1–22.

Wilson, D. R., & Price, J. S. (2006). Evolutionary epidemiology of endophenotypes in the bipolar spectrum: Evolved neuropsychologic mechanisms of social rank. Current Psychosis & Therapeutics Reports, 4 (4), 176–180.

Wolpe, J. (1961). The systematic desensitization treatment of neuroses. The Journal of Nervous and Mental Disease, 132 , 189–203. https://doi.org/10.1097/00005053-196103000-00001

Wolpert, L. (2008). Depression in an evolutionary context. Philosophy, Ethics, and Humanities in Medicine, 3 (1), 8.

Wrosch, C., & Heckhausen, J. (2002). Perceived control of life regrets: Good for young and bad for old adults. Psychology of Aging, 17 (2), 340–350.

Wrosch, C., & Miller, G. E. (2009). Depressive symptoms can be useful: Self-regulatory and emotional benefits of dysphoric mood in adolescence. Journal of Personality and Social Psychology, 96 (6), 1181.

Wrosch, C., Scheier, M. F., Miller, G. E., Schulz, R., & Carver, C. S. (2003). Adaptive self-regulation of unattainable goals: Goal disengagement, goal reengagement, and subjective Well-being. Personality and Social Psychology Bulletin, 29 (12), 1494–1508. https://doi.org/10.1177/0146167203256921

Zampieri, F. (2009). Medicine, evolution and natural selection: An historical overview. The Quarterly Review of Biology, 84 (4), 1–23.

Zeifman, D. M. (2001). An ethological analysis of human infant crying: Answering Tinbergen’s four questions. Developmental Psychobiology, 39 (4), 265–285. https://doi.org/10.1002/dev.1005

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• Philos Trans R Soc Lond B Biol Sci
• v.366(1571); 2011 Jun 12

Facial attractiveness: evolutionary based research

Anthony c. little.

1 Department of Psychology, University of Stirling, Stirling FK9 4LA, UK

Benedict C. Jones

2 School of Psychology, University of Aberdeen, Aberdeen, UK

Lisa M. DeBruine

Face preferences affect a diverse range of critical social outcomes, from mate choices and decisions about platonic relationships to hiring decisions and decisions about social exchange. Firstly, we review the facial characteristics that influence attractiveness judgements of faces (e.g. symmetry, sexually dimorphic shape cues, averageness, skin colour/texture and cues to personality) and then review several important sources of individual differences in face preferences (e.g. hormone levels and fertility, own attractiveness and personality, visual experience, familiarity and imprinting, social learning). The research relating to these issues highlights flexible, sophisticated systems that support and promote adaptive responses to faces that appear to function to maximize the benefits of both our mate choices and more general decisions about other types of social partners.

1. Introduction

The human face has been a source of great interest to psychologists and other scientists in recent years because of the extraordinarily well-developed ability of humans to process, recognize and extract information from other's faces (see other papers in this volume). Our magazines and television screens are not just filled with any faces—they are filled with attractive faces, and both women and men are highly concerned with good looks in a potential partner [ 1 ]. Physical appearance is important to humans and certain features appear to be found attractive across individuals and cultures [ 2 ]. The same holds true across the animal kingdom; most non-human species rely on external traits, such as the size, shape and colour of adornments (e.g. feathers, fur and fins) to attract mates [ 3 ]. Research on animals has focused on individual traits that are attractive across individuals, and even species, such as symmetry [ 4 ].

Physical attractiveness has important social consequences. For example, beauty is associated with upward economic mobility, especially for women [ 5 , 6 ], attractive people have more dates than less attractive people [ 7 ], and people who have dated more attractive individuals report being more satisfied with their dates [ 8 , 9 ]. It has long been noted that there exists a ‘What is beautiful is good’ stereotype [ 10 ] ([ 2 , 11 , 12 ] for meta-analytical reviews of research on physical attractiveness stereotypes), whereby attractive individuals are perceived to possess a variety of positive personality attributions. In mock interviews, attractive people are more likely to be hired than less attractive individuals [ 13 ] and attractiveness can also influence judgements about the seriousness of committed crimes [ 14 ]. Outside the laboratory, attractive people also appear to lead favourable lives; attractive individuals pay lower bail [ 15 ] and are more likely to be hired for jobs [ 16 , 17 ] than less attractive individuals.

Despite research on social consequences, exactly what it is that makes a face beautiful remains poorly defined. One of the major deterrents in determining the features of an attractive face lies in the widespread belief that standards of attractiveness are learned gradually through exposure to culturally presented ideals (e.g. through the media in Western society) and this has also led to a general belief that cultures vary dramatically in what they perceive to be attractive [ 18 ]. If this were true, it would mean that attractiveness is arbitrary and what is beautiful now could, in a different time or place, be considered unattractive. The well-known phrase ‘beauty is in the eye of the beholder’ is a testament to our belief that attractiveness is ephemeral. For example, the philosopher David Hume is often quoted for making the argument that beauty, ‘is no quality in things themselves: it exists merely in the mind which contemplates them; and each mind contemplates a different beauty’ [ 19 , pp. 208–209].

Darwin [ 20 ] was also struck by cultural differences, such as those evident in preferences for skin colour, body hair and body fat, and those revealed in practices such as lip ornamentation and teeth filing, ‘It is certainly not true that there is in the mind of man any universal standards of beauty with respect to the human body’ (Darwin cited by [ 21 ]). Such convictions were supported by early cross-cultural work by Ford & Beach [ 22 ] who catalogued differences between cultures in preferences for body weight, breast size and other aspects of female physique and suggested little consensus.

While individual and cross-cultural differences exist (see later), this politically correct view of beauty is to some extent false. In fact, agreement between individuals is one of the best-documented and most robust findings in facial attractiveness research since the 1970s. Across many studies it has been found that there is a high degree of agreement from individuals within a particular culture and also high agreement between individuals from different cultures (see [ 2 ] for a meta-analytical review). If different people can agree on which faces are attractive and which are not attractive when judging faces of varying ethnic background (e.g. [ 23 ]), then this suggests that people everywhere are all using the same, or at least similar, criteria in their judgements.

Cross-cultural agreement on attractiveness is evidence against the notion that attractiveness ideals are slowly absorbed by those growing up within a particular culture and this suggests that there is something universal about attractive faces (and unattractive faces) that is recognized both across individuals and cultures. In the next section, we discuss traits that are proposed to be generally attractive by reasoning based on evolutionary theories, but we return to the notion of individual variation later. While some traits are proposed to be on average preferred across individuals, an adaptive view of preference suggests that individuals will indeed vary in what they prefer and we examine differences in more detail in §3.

2. The evolutionary basis of attraction: the functions of beauty

An evolutionary view assumes that perception and preferences serve an adaptive function: the external world provides information to guide biologically and socially functional behaviours [ 24 ]. If in our evolutionary past, information was present about a person's mate and/or social value (e.g. provisioning ability, genetic quality) in any way, then an advantage would accrue to those who used these signs and those individuals would leave more genes behind in the next generation. Theoretically then, preferences guide us to choose mates who will provide the best chance of our genes surviving. In many studies, this evolutionary view of attractiveness has been used to predict the specific characteristics of attractive faces (see [ 25 ] for review). Sexual selection is the theoretical framework for much work and a thorough discussion of this topic in general is beyond the current review. Interested readers can see Andersson [ 3 ] for a thorough review, including issues relating to how preferences may arise in populations.

Although we can say whether a face is attractive or unattractive, it is extremely difficult to articulate the specific features that determine this attraction. There are, however, several facial traits that have been proposed to advertise the biological quality of an individual in human faces, and hence to influence attractiveness as a mate: traits such as symmetry, averageness and secondary sexual characteristics (see also [ 26 ] for meta-analysis). There are many aspects of ‘quality’ that can be associated with certain traits but these can be broadly split into two types of benefits to the perceiver: direct benefits, whereby the perceiver directly gains for themselves or their offspring, and indirect benefits, whereby the perceiver gains genetic benefits to their offspring. The former is relevant to both same- and opposite-sex attractiveness judgements, whereas the latter has consequences for reproductive pairings. For example, avoiding a parasitized mate has obvious direct advantages whether parasite resistance is heritable or not [ 27 ] as there are direct benefits to choosing a parasite-free mate. Preferences for facial traits that are associated with parasite resistance may be adaptive because this can lead individuals to associate with those who are not carrying contagious parasites (which may be passed on to the individual or to the offspring) and who are able to act as good parents (providing material benefits or care). Individuals who are attracted to those having face traits associated with parasite resistance may also increase the chances of passing on heritable parasite-resistant genes to their offspring. In other words, there are several reasons why avoiding a parasitized mate is advantageous. Ultimately it may be unnecessary to consider the relative weights of indirect and direct benefits; both indirect and direct benefits are likely to be important in evolution and their contributions to attractiveness are difficult to tease apart. We note that much research has focused on women's preferences, although most traits are also relevant for men.

(a) Symmetry

Symmetry refers to the extent to which one-half of an object (image, organism, etc.) is the same as the other half. Individuals differ in their ability to maintain the stable development of their morphology under the prevailing environmental conditions under which that development is taking place [ 28 , 29 ]. The ability of an individual to develop successfully in the face of environmental pressures is therefore one proposed indicator of genetic quality. A character demonstrates fluctuating asymmetry (FA) when symmetry reflects the normal development, and deviations from this symmetry are randomly distributed with respect to side [ 30 ]. FA is a particularly useful measure of developmental stability because we know that the optimal developmental outcome is symmetry. Therefore, any deviation from perfect symmetry can be considered a sub-optimal solution which will result in performance problems in the future. FA is also a useful measure as it subsumes a huge amount of individual variation in development, being the outcome of differences in genetic (e.g. inbreeding, mutation and homozygosity) and environmental (e.g. nutrient intake, parasite load) factors [ 28 , 29 ]. Preferences for symmetry can then, potentially, provide both direct (e.g. by avoiding contagion) and indirect benefits (e.g. by providing healthy genes for offspring) to the perceiver.

Whether symmetry is actually related to quality in other animals and humans is an issue addressed by a large literature, and a complete review is not the focus of this paper. While the issue is divided, and there is some evidence that symmetry is not associated with quality (e.g. [ 31 ]), many studies do show links between symmetry and quality in many species [ 28 , 29 ]. In humans, male body symmetry is positively related to sperm number per ejaculate and sperm speed [ 32 ] and female breast symmetry is positively correlated with fecundity [ 33 , 34 ]. Relating to faces, one study has demonstrated that facial asymmetry is positively related to self-reported number of occurrences of respiratory disease [ 35 ] and some studies have observed positive correlations between symmetry and other putative indices of underlying physical condition (i.e. exaggerated sex-typical characteristics, [ 36 , 37 ]). The relationship between symmetry and quality is not reviewed in detail here, but it should be noted that fitness-related characteristics, such as growth rate, fecundity and survivability, are positively associated with symmetry across a number of species and taxa (e.g. [ 29 ]; see [ 38 ] for a review) and ultimately, any link between symmetry and quality, no matter how weak, is sufficient to create a selection pressure on the opposite sex to choose symmetric mates in order to provide genetic quality benefits to their offspring.

In humans, Thornhill & Gangestad [ 39 ] found that the total number of sexual partners a man reported having was positively related to skeletal symmetry. Studies of naturally occurring human facial asymmetries also provide evidence that symmetry is found attractive, though such studies can be confounded by potential correlates. Studies measuring symmetry from unmanipulated faces have reported positive correlations with rated attractiveness [ 40 – 44 ] and one study has even demonstrated that with pairs of monozygotic twins, the twin with more symmetric measurements is seen as more attractive [ 45 ].

While some studies directly manipulating human facial images have found that asymmetry is preferred to symmetry [ 46 ], manipulations used in these studies tend to be crude, using ‘chimeric’ face images manufactured by aligning one vertically bisected half-face with its mirror reflection. Studies using more sophisticated symmetry manipulations have demonstrated that symmetry can have a positive influence on attractiveness [ 47 , 48 ] and have established that the chimeric manipulations used in the early studies introduced unnatural proportions into the symmetric faces (see [ 48 ]). Examples of manipulated images can be seen in figure 1 . Thus, the methodologically superior computer graphic studies [ 47 , 48 ] parallel the findings of investigations into naturally occurring facial asymmetries [ 40 , 41 , 43 – 45 ]. The computer graphic studies demonstrate that increasing symmetry alone is sufficient to increase attractiveness. Subsequently, other studies have replicated preferences for symmetry using manipulated stimuli in different Western samples (e.g. [ 49 , 50 ]), but evidence for symmetry preferences using these methods is not limited to western populations or even to humans. Preferences for symmetry using manipulated faces have been found in African hunter–gatherers [ 51 ], and macaque monkeys gaze longer at symmetrical than at asymmetrical face images of conspecifics [ 52 ].

Symmetry and asymmetry. ( a ) A shape-symmetric facial composite and ( b ) asymmetric version. Features and outline are marked on the faces in order to create symmetric/asymmetric versions. The asymmetric version has had its asymmetry enhanced by 50%. Symmetric images are usually preferred to asymmetric images.

Importantly, recent studies have implicated perceptions of health in attraction to symmetric faces [ 44 , 53 ] and have suggested that the mechanisms underpinning preferences for symmetric faces are different from those that might drive preferences for symmetry in mate-choice-irrelevant stimuli (e.g. [ 49 , 50 ]). Such findings suggest that preferences for symmetric faces reflect, at least in part, adaptations for mate choice.

(b) Averageness

Averageness refers to how closely a face resembles the majority of other faces within a population; non-average faces have more extreme characteristics than the average of a population. Average faces may be attractive because an alignment of features that is close to a population average is linked to genetic diversity [ 54 , 55 ]. Thornhill & Gangestad [ 54 ] have argued that average faces may be preferred to less-average faces because owners of average faces possess a more diverse set of genes, which may result in less common proteins to which pathogens are poorly adapted. Parasites are generally best adapted to proteins that are common in the host population; hence, parasites are adapted to the genes that code for the production of these proteins. A second evolutionary theory for the attractiveness of averageness in faces is that extreme (non-average) genotypes are more likely to be homozygous for deleterious alleles, that is, to be more likely to possess genes that are detrimental to an individual than those with more average genotypes [ 54 ]. Both of these theories propose evolutionary benefits to mating with individuals possessing average faces.

Recent studies have supported the link between averageness, heterozygosity (i.e. genetic diversity) and attractiveness. Heterozygosity in the major histocompatibility complex (MHC) genes that code for proteins involved in immune response, is positively associated with facial attractiveness [ 56 ] and facial averageness [ 57 ]. More directly, another study has shown that facial averageness is positively related to medical health as measured from actual medical records in both men and women [ 58 ]. Facial averageness can then be potentially associated with both direct benefits in terms of associating with healthy, parasite- and/or disease-free partners and indirect benefits of heterozygous genes that can be passed onto offspring.

There is good evidence that average faces are indeed found attractive. Galton [ 59 ] first noted that multiple faces blended together were more attractive than the constituent faces. Recent studies have improved upon these techniques using computers to create digitally blended composite faces; generally, the more images in a composite, the more attractive it is found [ 60 – 62 ]. Aside from composite images, Light et al. [ 63 ] found that, in unmanipulated male faces, more attractive faces were rated as less distinctive, and Rhodes & Tremewan [ 64 ] found that higher averageness was associated with higher attractiveness when manipulating averageness via digital caricaturing.

Average faces are generally more symmetric and symmetry is typically attractive in faces (discussed in more detail above). Several studies have controlled for this confound in the original studies. When averageness and symmetry were independently manipulated, one study found that both manipulations positively and independently influenced attractiveness judgements [ 65 ]. Other studies have used perfectly symmetric images manipulated in averageness and still have demonstrated preferences for averageness [ 66 , 67 ]. Indeed, by comparing preferences for averageness when the effects of symmetry were controlled for and were not controlled for, Jones et al . [ 66 ] demonstrated that the contribution of symmetry to the attractiveness of average faces was minimal.

It has also been noted that, in the original composite studies, the more images that are blended together the smoother the skin texture becomes, as imperfections such as lines or blemishes are averaged [ 68 ]. Skin colour/texture has been controlled in studies that normalize the texture/colour of all the faces seen and all these studies demonstrate that average is attractive [ 62 , 64 , 66 , 67 ]. Examples of composite images and the effects of shape and colour averaging can be seen in figure 2 .

Averageness. ( a ) A composite image made from three images, ( b ) the same image given the colour of nine images and ( c ) a shape and colour composite made from nine images. Image ( c ) should be more attractive than both of the other images. Composites are made by marking key locations around the main facial features (e.g. points outline the eyes, nose and mouth) and the outline of each face (e.g. jaw line, hair line). The average location of each point of the component faces is then calculated to define the shape of the composite. The images of the individual faces are then warped to the relevant average shape before superimposing the images to produce a photographic quality composite image.

While the majority of the work described above has been carried out in North America, Britain and Australia, averageness has also been found to be attractive across different cultures. For example, facial averageness is also found attractive in Japanese participants [ 69 ] and in African hunter–gatherers [ 67 ].

(c) Secondary sexual characteristics in faces

Male and female faces differ in their shape. Mature features in adult human faces reflect the masculinization or feminization of secondary sexual characteristics that occurs at puberty. These face shape differences, in part, arise because of the action of hormones such as testosterone. Larger jawbones, more prominent cheekbones and thinner cheeks are all features of male faces that differentiate them from female faces (e.g. [ 70 ]).

From an evolutionary view, extremes of secondary sexual characteristics (more feminine for women, more masculine for men) are proposed to be attractive because they advertise the quality of an individual in terms of heritable benefits; they indicate that the owners of such characteristics possess good genes. In other words, such traits advertise the possession of genes that are beneficial to offspring inheriting them in terms of survival or reproduction. One explanation of the importance of these facial traits is that they represent a handicap to an organism [ 71 ] and the costs of growing the trait means that only healthy individuals can afford to produce them. In this way, these ‘honest’ handicaps are proposed to indicate the fitness of the owner. For example, secondary sexual characteristics are proposed to be linked to parasite resistance because the sex hormones that influence their growth, particularly testosterone, lower immunocompetence. Testosterone has been linked to the suppression of immune function in many species [ 72 ], including humans [ 73 , 74 ]. Larger secondary sexual characteristics should be related to a healthier immune system because only healthy organisms can afford the high sex-hormone handicap on the immune system that is necessary to produce these characteristics [ 75 ].

In many non-human animal studies, there is a positive association between secondary sexual trait expression and immunocompetence (e.g. [ 76 ]). The relationship between masculinity/femininity and good genes in humans is less clear. A study by Rhodes et al . [ 77 ], however, has shown that perceived masculinity correlated positively with actual measures of health in male adolescents. No relationship was found between femininity and actual health in female faces, though [ 77 ]. Another study has demonstrated that men's facial masculinity and women's facial femininity are negatively related to self reports of respiratory disease [ 35 ]. If health is heritable, then female preferences for masculinity and male preferences for femininity may indeed also reflect the choice of mates with good genes. There is also a link between hormonal profile and face shape. Women with higher circulating oestrogen have more feminine faces [ 78 ], while men with high testosterone have more masculine faces ([ 79 ], but see also [ 80 ]). If women with high oestrogen and men with high testosterone are valued as mates, preferences for cues of hormonal profile could drive preferences for sexually dimorphic face shape. Figure 3 shows faces manipulated in facial masculinity and femininity.

Masculinity/femininity in faces. ( a ) Male and female composite images made more masculine and ( b ) more feminine. Masculinity is transformed using the difference between male and female face shape as defined by creating a male and female composite. Preferences for masculinity in male faces vary across studies, but feminine female faces are consistently found more attractive than masculine female faces.

There is considerable evidence that feminine female faces are considered attractive. Studies measuring facial features from photographs of women [ 40 , 81 , 82 ] and studies manipulating facial composites [ 83 ] all indicate that feminine features increase the attractiveness of female faces across different cultures. If oestrogenized female faces provide cues to fertility and health, then male preferences for such features are potentially adaptive. This reasoning does not require oestrogen to be immunosuppressive or part of a handicap.

The link between masculinity and attractiveness in male faces is less clear. Cunningham et al . [ 84 ] and Grammer & Thornhill [ 40 ] used facial measurements and found that women preferred large jaws in men. ‘Masculine’ features, such as a large jaw and a prominent brow ridge are reliably associated with ratings of dominance in photographic, identikit and composite stimuli [ 83 , 85 – 88 ]. Despite some findings showing a preference for more masculine and dominant faces, several studies have shown that feminine characteristics and faces of low dominance are of increased attractiveness [ 62 , 83 , 84 , 89 – 91 ]. Many studies have made use of computer graphic techniques to manipulate masculinity. Sexual dimorphism in face shape can be manipulated by taking the geometrical differences between average male and female face shapes and applying this difference to new faces, making more or less masculine or feminine versions [ 83 ]. This process simultaneously changes all dimorphic shape characteristics in the face. For example, ‘masculinizing’ a male face shape by increasing facial proportions relative to the differences between a male and female average increases the size of the jaw and reduces lip thickness because male jaws are larger than female jaws and the lips of men are thinner than those of women. Perrett et al . [ 83 ] presented both Japanese and Caucasian faces in their country of origin. For the male face stimuli, the shape selected by Caucasians as most attractive was significantly feminized for both the Caucasian male face and the Japanese male face continua. Similarly, Japanese participants also selected significantly feminized versions of the male stimuli for both the Japanese and Caucasian male face continua. Thus, in both cultures it was found that participants showed a preference for feminized male faces. Since then, several studies have also documented preferences for femininity [ 62 , 90 , 92 , 93 ], but some similar computer graphic studies have also reported preferences for masculinity [ 94 , 95 ]. Although some of this variation may be attributed to other characteristics of the faces that varied between sets of stimuli [ 96 ], this does not explain the variability in preferences. We discuss the sources of individual differences in preferences for sexually dimorphic shape cues in the latter sections of our article.

(d) Skin health and colour

The face traits discussed so far have often been measured and manipulated but also studied in terms of perception and related to attractiveness. The reasoning for why traits like symmetry are preferred is often related to underlying health. Thus, it is important to examine perceptions of facial health directly. Perceived health is difficult to relate to any one metric, but people will readily rate faces for perceived health and show very high agreement on such ratings (e.g. [ 44 , 97 ]). See figure 4 for examples of healthy and unhealthy appearing traits. In evolutionary terms, there is a large and obvious selective advantage in detecting healthy partners both for social exchange and mate choice. Indeed, while the role of health in mate preferences is clear (see below), recent work has demonstrated that participants are more willing to reciprocate trust from healthy-looking social partners than from social partners who are relatively unhealthy-looking [ 98 ]. Such findings demonstrate the importance of health perceptions for social interaction generally. Again, as for previous traits, there may be both direct and indirect benefits to partnering with individuals who are perceived to be healthy.

Facial healthiness. ( a ) Composite images of 15 women rated as high on healthiness and ( b ) 15 women rated as low on healthiness. High healthiness is associated with higher ratings of attractiveness.

There have been several studies that have addressed how facial appearance relates to the healthiness of an individual in humans. The three traits discussed above are often manipulated by changing only face shape, but health perception appears to be related to facial colour and texture also. Fewer studies have examined how colour and texture of faces influence attractiveness judgements. One study has examined how well ratings of health from small patches of skin of faces are related to overall rated attractiveness when the whole face image is available. Jones et al . [ 43 ] found that apparent health of facial skin is positively correlated with ratings of male facial attractiveness. In other research, homogeneity of skin colour was positively related to attractiveness [ 99 ]. Findings have also suggested that more heterozygous men also have healthier appearing skin [ 56 ]. Skin health may be a particularly useful marker of current health condition as it is more changeable than aspects such as symmetry or averageness.

Coloration is directly related to the appearance of skin. Coloration also appears to be an important component of sexual selection in many species. Red coloration is associated with dominance in fish [ 100 ], birds [ 101 ] and non-human primates [ 102 , 103 ] and, consequently, is linked to attracting the opposite sex. Recent evidence has suggested that primate trichromatic vision is an adaptation to distinguish colour modulations in skin based on blood flow, allowing assessment of the state and/or mood of conspecifics [ 104 ]. It has been noted that primates with trichromatic vision are generally bare-faced [ 104 ] and that, at least in humans, facial flushing is associated with anger and confrontation [ 105 ].

In research on non-human primates, there has been much interest in colour. For example, experimental manipulation of colour shows that female rhesus macaques prefer images of redder male faces [ 103 ], while males prefer images of redder female hindquarters [ 106 ]. In mandrills, red facial colour is related to rank in males [ 102 ], and females sexually present more frequently to brighter males and also groom them more frequently [ 107 ]. Red coloration also has consequences for behaviour in other species. For example, in bird species, the addition of red to stimuli can increase social dominance [ 108 ].

In humans, it has been shown that wearing red in a variety of physically competitive sports is associated with an increased chance of winning over opponents [ 109 ]. This has been interpreted as natural associations of red with dominance being extended to artificially displayed red in the same way that artificial stimuli can exploit innate responses to natural stimuli [ 108 , 110 ]. One study pitting red versus blue shapes found that red shapes were seen as more aggressive, dominant and more likely to win in physical competitions [ 111 ]. Red does generally seem to have aversive effects on human behaviour. For example, when taking exams, individuals move their body away from tests with red covers more than they do from those with green or grey covers [ 112 ]. While these studies suggest the colour red may be seen as a threatening stimulus in humans, red also appears to enhance attraction in some instances. For example, women are seen as more attractive by men when presented with red backgrounds or with red clothing, relative to other colours [ 113 ]. This effect appears to be specific to attractiveness judgements; red colour does not influence judgements of other traits such as kindness or intelligence and does not influence women's attractiveness judgements of other women [ 113 ]. Further research has examined red coloration in faces and demonstrated a positive association with perceived health [ 114 ]. The authors suggest that perception of healthy, oxygenated blood may drive associations between red and healthiness. Alongside redness, people also appear to think that skin yellowness is associated with healthy appearance in faces [ 114 ]. Yellowness may advertise health via an association with diet, as carotenoids are associated with skin yellowness and are absorbed via the intake of fruit and vegetables [ 114 ]. Taken together, these studies suggest that information on attractiveness and health is available from surface skin and that facial attractiveness is not dependent only on traits that display limited variation in adult life: skin texture and skin colour can vary over weeks or even days.

(e) Facial cues associated with personality attribution

In a classic social psychology study, Dion et al . [ 10 ] found that strangers rated attractive people as possessing ‘socially desirable’ traits to a greater extent than unattractive people, and that attractive people were also expected to lead better lives than unattractive people. For example, attractive individuals were thought to be able to achieve more prestigious occupations, be more competent spouses with happier marriages and have better prospects for personal fulfilment. There has been a wealth of studies examining this attractiveness stereotype, demonstrating that attractive people are seen in a positive light for a wide range of attributes compared with unattractive people. On the basis of such studies, it has been suggested that there exists a stereotype associated with physical attractiveness, famously—‘What is beautiful is good’ [ 2 ] (see [ 11 , 12 ] for meta-analytical reviews of research on physical attractiveness stereotypes).

Studies on attractiveness stereotypes have generally not addressed the particular characteristics of faces that make individuals either attractive or unattractive, or the features that elicit personality attributions, although different faces reliably elicit the same personality attributions [ 115 ]. Expression certainly has large effects, with, for example, faces shown with smiles rated as more attractive and as having more positive personality traits than neutral faces (e.g. [ 116 ]). Such facial expressions are transient, however, and will differ rapidly within individuals over time and across photographs. Both baby-like and mature/dominant facial qualities are related and are more stable aspects of appearance that reliably elicit personality attributions cross-culturally (e.g. [ 88 , 117 ]), but their effect on attractiveness judgements, at least of men, is still in dispute, as noted earlier. Despite some findings showing a preference for more masculine and dominant male faces (e.g. [ 40 ]), several studies have shown that feminine characteristics and faces of low dominance are of increased attractiveness [ 84 , 89 ].

Personality traits are reported cross-culturally to be among the most important factors in partner choice by both sexes [ 1 , 118 ]. If desired personality is so important, it would appear likely that personality attributions elicited by a face would affect its attractiveness. For example, women who value cooperation and good parenting may avoid masculine-faced men. Thus, instead of feminine faces being attractive and this attractiveness driving positive personality attributions, it may be that the personality attributions are driving the attractiveness judgements.

Individuals may use personality stereotypes in mate selection to select partners with a personality that they desire. Some perceptual attributions to facial photographs are somewhat accurate (e.g. [ 119 ]), and so choosing a partner based on perceived personality may result in acquiring a partner who actually possesses desired personality traits. Attraction to faces based on personality stereotypes may happen regardless of whether attributions are accurate or not, especially as many individuals do believe that face provides an important guide to character [ 115 , 120 ]. In fact, it is possible that visually appearing to possess certain traits may be more important in initial selection processes than actually possessing desired traits because the visual stereotypes are more easily available than information about stable behaviour. One study has indeed demonstrated that a desire for some personality traits influences judgements of facial attractiveness [ 121 ]. Individuals valuing particular personality traits find faces appearing to display these traits attractive. Conversely, those not valuing particular traits find faces attractive that are perceived to possess that trait less. Thus, desired personality influences perceptions of facial attractiveness in opposite sex faces, changing the result to: ‘what is good is beautiful’ [ 121 ]. In terms of benefits to perceivers, it is easy to see why traits such as appearing trustworthy would make a face appear more attractive. For individual-specific traits, the logic is more complicated, but such preferences could be related to behavioural compatibility within couples, as people do tend to desire partners with personalities similar to their own [ 122 ].

One reason for variability in preferences for male facial masculinity may lie in the personality traits that masculine- and feminine-faced men are assumed to possess. Increasing the masculinity of face shape increased perceptions of dominance, masculinity and age but decreased perceptions of warmth, emotionality, honesty, cooperativeness and quality as a parent [ 83 ]. Cunningham et al . [ 84 ] have suggested that, because both masculine and feminine faces are only rated as moderately attractive, a resolution to this conflict could be that very attractive male faces possess a combination of factors and so reflect ‘multiple motives’ in female mate choice (i.e. the desire for a dominant and a cooperative partner, as advertised by a combination of masculine and feminine features). It appears then that ‘socially valued’ traits such as honesty, warmth, cooperation and skill as a parent are associated with feminized versions of male faces, while traits such as dominance are associated with masculinized face shapes. Indeed, recent work has shown that masculine facial characteristics are associated with indices of physical dominance, such as physical strength [ 123 ], and the perception of such traits [ 124 ], and that feminine men show weaker preferences for short-term relationships and stronger preferences for committed, long-term relationships than their masculine peers do [ 125 ]. Feminization of male face shape may increase attractiveness because it ‘softens’ particular features that are perceived to be associated with negative personality traits. Women's face preferences may thus represent a trade-off between the desire for good genes and the desire for a cooperative partner. This trade-off means that masculinity may be more or less attractive under certain contexts and to certain individuals; we discuss this in §3.

(f) Other traits and interactions

Of course, the five types of trait listed above are not a complete list of factors involved in the judgement of facial attractiveness. Other face traits include factors such as age [ 126 ], weight/adiposity [ 127 ], hair and eye colour [ 128 ], facial hair in men [ 129 ] and make-up use in women [ 130 ]. Similarity to self also appears to be an influential trait and we review this factor in more detail in §3 b as self-similar preferences vary according to social context [ 131 , 132 ].

While individual traits impact on attractiveness, there is also scope for interaction between them. We review studies on interactions between emotion and attention in §3 b as preferences for these traits also change according to social context. Certain face traits also appear to interact in generating preferences, however. For example, preferences for masculinity vary as a function of the healthiness of the face [ 96 ] and women's preferences for facial self-similarity are higher when men are more facially masculine [ 133 ]. Such interactions highlight that facial attractiveness judgements are not simple: many factors contribute to facial attractiveness and these factors can interact with one another.

3. Adaptive individual differences

In humans, while individuals may share certain basic criteria for finding faces attractive, many factors may influence the specific types of face they find attractive. In this section, we review three broad areas leading to individual differences in preferences: internal factors (e.g. hormonal state), context (e.g. mate-choice versus same-sex preferences) and exposure (e.g. visual experience).

(a) Internal factors

Research suggests that internal factors predict individual differences in several aspects of face perception, including attractiveness judgements. Importantly, the nature of these individual differences suggests adaptive design in face perception and face preferences. In the following section, we discuss two broad types of internal factors: (i) those related to hormone levels and fertility and (ii) those related to own condition, attractiveness and personality.

(i) Hormone levels and fertility

The influence of hormones on face perception is an area that has generated a considerable amount of empirical research in recent years. As detailed previously, masculine characteristics in men's faces are associated with measures of long-term medical health [ 35 , 77 ] and indices of developmental stability [ 36 , 37 ], physical strength [ 123 ] and reproductive potential [ 134 ]. By contrast, feminine characteristics in men's faces are associated with cues of investment and stronger preferences for long-term over short-term sexual relationships (e.g. [ 125 ]). There is now compelling evidence that how women resolve this trade off between the costs and benefits associated with choosing a masculine mate is affected by hormone levels and fertility.

Many studies have reported that women demonstrate stronger preferences for men displaying masculine facial characteristics around ovulation, when women are most fertile, than during other phases of the menstrual cycle [ 135 – 138 ]. Some studies have also reported that these cyclic shifts in women's preferences for masculine characteristics in men's faces are greatest among women who already have romantic partners and when women judge men's attractiveness for short-term, extra-pair relationships [ 138 ]. Although the ultimate function of these cyclic shifts remains somewhat controversial, many researchers have interpreted cyclic shifts in women's masculinity preferences as evidence for adaptations that function to increase offspring health via high paternal investment from a long-term partner while promoting attraction to other men displaying cues of heritable immunity to infectious disease when most fertile (discussed in [ 139 ]). Women may gain maximal benefits by selecting investing long-term partners and high-quality extra-pair partners. Importantly, other explanations that have been suggested, such as increased attraction to individuals who appear to be likely sources of high-quality care and support during phases of the menstrual cycle when increased progesterone prepares the body for pregnancy (i.e. the non-fertile, luteal phase), are not necessarily mutually exclusive with the more widely posited accounts that emphasize indirect benefits of women's mate choices (discussed in [ 140 ]). Increased attraction to masculine men is by no means unique to face preferences; women also demonstrate stronger attraction to masculine men when judging the attractiveness of men's voices [ 141 – 143 ], body shapes [ 144 ] and body odours [ 145 ], as well as when judging the attractiveness of videoclips of male behavioural displays of dominance [ 146 , 147 ]. Furthermore, converging evidence for fertility-related variation in women's preferences for facial masculinity comes from studies investigating circum-pubertal and circum-menopausal variation in women's masculinity preferences; post-menopausal and pre-pubertal women report weaker preferences for masculine facial characteristics than do their pre-menopausal and post-pubertal counterparts, respectively (e.g. [ 148 , 149 ]).

The ultimate function of cyclic shifts in women's preferences for masculine facial characteristics is not the only controversial aspect of cyclic shifts in women's masculinity preferences. For example, although some researchers have suggested that cyclic shifts in women's masculinity preferences may be an artefact of the computer graphic methods that are generally used in these studies to experimentally manipulate sexually dimorphic cues in digital face images [ 150 ], this claim is very difficult to reconcile with findings from studies that have demonstrated cyclic shifts in women's preferences for masculinity in real (i.e. unmanipulated) face images [ 151 ] and with the converging evidence for cyclic shifts in women's preferences for masculinity from studies that have assessed preferences for masculinity in other domains (e.g. behaviour, personality descriptions, body odour) and that did not use computer graphics to prepare their stimuli (e.g. [ 146 , 147 ]). While these findings suggest that cyclic shifts in women's masculinity preferences are not an artefact of the stimuli used, an aspect of research on cyclic shifts in women's masculinity preferences that remains controversial is whether the effect of cycle phase on women's face preferences is relatively specific to judgements of men's faces, or also occurs when women judge the attractiveness of other women. To date, evidence is equivocal; some studies have observed cyclic shifts in women's preferences for masculine-faced men, but not masculine-faced women [ 135 ], while others have observed cyclic shifts in women's preferences for masculine faces, irrespective of their sex [ 136 , 152 ]. These latter papers speculate that cyclic shifts in women's preferences for masculine-faced women could represent a low-cost functionless by-product of a mechanism that evolved primarily to increase women's preferences for masculine men around ovulation [ 136 ], or have suggested that higher attractiveness ratings given to masculine women around ovulation could reflect increased derogation of feminine, and therefore attractive, same-sex competitors when women are most fertile [ 152 ] (see also [ 149 ]).

In addition to the sex-specificity of the effects of cycle phase on face preferences, the mechanisms that underpin cyclic shifts in women's preferences for masculine characteristics in men's faces have also been a topic of considerable interest in recent years. For example, research into the hormonal mechanisms that might underpin these cyclic shifts has variously emphasized the effects of variation in levels of testosterone [ 152 ], oestrogen [ 153 ] and progesterone [ 136 , 141 ], or has suggested, perhaps unsurprisingly, that cyclic shifts in women's masculinity preferences might be best explained by complex interactions among multiple hormones [ 142 , 152 ]. While findings from research into the hormonal mechanisms that might underpin cyclic shifts in women's masculinity preferences have arguably been inconsistent, the findings of corresponding research into the psychological mechanisms have been relatively consistent; various studies have demonstrated that women are quicker to categorize men and access male stereotypes around ovulation (e.g. [ 154 , 155 ]) or have suggested that women's preferences for masculine men are correlated with their level of sexual desire [ 156 , 157 ]. These findings suggest that cyclic variations in stereotype access and sexual desire might be important psychological mechanisms for regulating facial masculinity preferences during the menstrual cycle.

While research on hormone-mediated face perception has generally focused on women's judgements of men's attractiveness, some recent research has investigated hormone-mediated face preferences among men. Men, of course, do not cycle in the same way women do, but levels of testosterone fluctuate within individuals. Research using natural variation in testosterone has shown that men's preferences for feminine characteristics in women's faces are stronger when their testosterone levels are high than when they are relatively low [ 158 ]. This finding suggests that hormones, such as testosterone, can generate within-participant individual differences in face preference in men.

As can be seen from the previous paragraphs, there is compelling evidence that women's preferences for masculine men, be they assessed from face preferences or from preferences for male characteristics in other domains, vary systematically over the menstrual cycle. Whether or not preferences for other putative cues of men's long-term health are similarly affected by menstrual cycle is equivocal, however. For example, although many studies have demonstrated that women's preferences for the body odours of symmetric men are enhanced around ovulation (reviewed in [ 139 ]), evidence for cyclic shifts in women's preferences for symmetry in men's faces is inconsistent. One study has found that women's preferences for symmetric male faces were stronger around ovulation than during other phases of the menstrual cycle, at least among partnered women who were instructed to judge men's attractiveness as short-term mates [ 159 ]. By contrast, other studies have observed no evidence for cyclic shifts in women's preferences for symmetric men's faces (e.g. [ 150 ]), although one study with a null finding for preference did find that women's ability to detect asymmetries in men's faces varied over the menstrual cycle in the predicted manner [ 160 ]. Given that women's preferences for symmetry and masculinity in men's faces are correlated across individuals [ 161 ], suggesting that facial masculinity and symmetry signal some shared information and that women respond to them in similar ways, the inconsistent effects of cycle phase on women's preferences for facial symmetry are rather surprising.

Although evidence that women's preferences for symmetry in men's faces vary systematically over the menstrual cycle is equivocal, that is not to say that robust cyclic shifts in women's perceptions of faces are only evident in their preferences for facial masculinity. For example, women's aversions to self-resembling faces are enhanced around ovulation and positively correlated with women's estimated progesterone levels during the menstrual cycle [ 162 ]. This variation in attitudes to self-resembling faces may reflect increased inbreeding avoidance around ovulation and increased preferences for caring, supportive and trustworthy individuals when increased progesterone prepares the body for pregnancy [ 163 ]. Moreover, women's aversions to facial cues associated with current illness (e.g. pallor) are also greater when increased progesterone level prepares the body for pregnancy, potentially reflecting mechanisms to compensate for maternal immunosupression during the early stages of pregnancy and helping to maintain normal foetal development [ 97 , 136 ]. Indeed, pregnant women and women using oral contraceptives which mimic the effects of increased progesterone during pregnancy demonstrate stronger aversions to individuals displaying facial cues of illness than do women with natural menstrual cycles [ 97 ]. These latter findings for aversions to facial cues of illness and progesterone during the menstrual cycle complement other research on increased aversions to possible sources of contagion in women's food preferences during pregnancy [ 164 ], as well as increased sensitivity to facial expressions signalling that sources of threat and contagion are nearby when progesterone levels are raised [ 165 , 166 ].

While our discussion of hormone-mediated face preferences in women has emphasized the positive findings that have been reported in the literature, it is important to note that there have also been unsuccessful replications of cyclic variation in women's face preferences. For example, two recent studies observed no evidence for cyclic variations in women's preferences for masculine versus feminine male faces [ 150 , 167 ]. One possible explanation of these null findings comes from findings that suggest the extent to which women's preferences for masculine men vary over the menstrual cycle vary systematically among women. For example, cyclic variation in women's preferences for masculine characteristics in men's voices is significantly greater among women with high trait (i.e. average) oestrogen levels than it is among women with relatively low trait oestrogen levels [ 142 ]. This pattern of results may occur because varying their sexual strategy during the menstrual cycle may benefit unattractive women more than it benefits attractive women [ 142 ]. More recent research has presented additional evidence that women's family background, prenatal hormone levels and mortality salience might also affect the extent to which they vary their masculinity preferences according to their menstrual cycle phase [ 168 – 170 ]. We also note that there are significant methodological differences between studies examining cycle effects, making direct comparisons (e.g. between those reporting null and positive effects) difficult. For example, some studies distinguish between short- and long-term mating contexts, generally with larger cyclic shifts for short-term judgements [ 139 ], while others do not [ 167 ]. Studies also differ in stimuli number, stimuli type and how fertility is defined. A thorough description of methodological differences between studies is not the focus here, but methodology is certainly a factor that could explain differences in findings across studies. It is likely that further research concerning individual differences in cyclic shifts and comparing different methodologies would provide important insights into the motivations, functions and mechanisms behind cyclic shifts in fundamental aspects of face perception.

(ii) Own condition, attractiveness and personality

While the previous section discussed research implicating hormone levels and fertility in individual differences in face perception, this section will discuss the relationships between face preferences and indices of own condition and attractiveness.

Several studies have reported positive correlations between women's ratings of their own physical attractiveness and the strength of their preferences for masculine characteristics in men's faces [ 92 ]. Other studies have extended this work by demonstrating that more objective measures of women's condition and attractiveness, such as their waist–hip ratio or oestrogen levels, predict their preferences for masculine characteristics in men's faces in the same way [ 171 , 172 ]. Similar correlations between indices of women's own attractiveness and the strength of their preferences for masculine characteristics in other domains, such as men's voices, have also been reported [ 173 , 174 ], and indices of women's own condition and attractiveness are positively correlated with the strength of their preferences for symmetry and healthy-looking skin in men's faces [ 92 , 175 ].

The findings described above appear to be somewhat analogous to condition-dependent preferences observed in other species, in which individuals in good physical condition show stronger preferences for high-quality mates (e.g. [ 176 ]). Condition-dependent preferences in both humans and non-humans may have a common function and occur because individuals in good physical condition (i.e. attractive individuals) are better able to compete for and/or retain high-quality mates [ 92 ]. Particularly compelling evidence for this proposal comes from one of the few experimental studies of condition-dependent mate preferences. Little & Mannion [ 95 ] showed that women who viewed a slideshow of highly attractive women reported lower self-rated attractiveness and demonstrated weaker preferences for masculine characteristics in men's faces than did women who viewed a slideshow of relatively unattractive women. These findings suggest that women recalibrate subjective impressions of their own attractiveness (i.e. impressions of their own ‘market value’) according to their recent experience with same-sex competitors and that this, in turn, leads to a recalibration of their mate preferences. While early work on the role of own attractiveness in mate preferences emphasized the importance of the judge's own health, Little & Mannion's findings suggest that condition-dependent preferences might be more usefully conceptualized as ‘market value dependent preferences’.

While the research described above focused on the relationships between mate preferences and both individuals' own physical characteristics and their subjective evaluations of these physical characteristics, other work on condition-dependent preferences has investigated whether personality traits and other psychological factors predict individual differences in mate preferences in similar ways. For example, individual differences in systemizing and sensation-seeking, both of which are components of male sex-typical psychology, are positively correlated with men's preferences for feminine characteristics in women's, but not men's, faces [ 177 , 178 ]. Among women, individual differences in empathy, a component of female sex-typical psychology, and extraversion, a key predictor of social status that is correlated with women's physical attractiveness, are positively correlated with preferences for masculine characteristics in men's, but not women's, faces [ 177 , 179 ]. These findings not only implicate personality traits in individual differences in face preferences but also raise the intriguing possibility that some personality traits might mediate the relationships between an individual's physical characteristics and their face preferences.

(b) Context

While factors such as hormones and own attractiveness can explain differences in face preferences between individuals, the context under which judgements are made can also contribute to variation in standards of beauty. In the following section, we discuss how context affects face preferences in three types of contexts: (i) social contexts, such as when judging potential mates versus potential cooperative partners; (ii) temporal contexts, such as long- versus short-term relationships; and (iii) environmental contexts, such as environments with high versus low pathogen load.

(i) Social context

Information about genetic kinship is available in the face and is perceived somewhat accurately [ 180 – 184 ]. Judgements of facial similarity are highly synonymous with judgements of kinship [ 185 – 187 ], and facial similarity produced by computer-graphic manipulation affects behaviour in ways consistent with inclusive fitness theory (e.g. increasing cooperation in economic games; [ 188 , 189 ]). Therefore, responses to facial resemblance are likely to be affected by prosocial versus sexual contexts.

Cues of kinship are predicted to increase preferences in non-sexual, prosocial contexts, owing to the benefits associated with inclusive fitness [ 190 ]. In other words, evolutionary models show that behaviours that benefit other individuals who share genes through common descent will be favoured. Therefore, if physical similarity is a reliable cue of genetic relatedness, we expect individuals to act prosocially towards individuals who appear similar to themselves. However, cues of kinship should have a less positive effect in sexual contexts, because of inbreeding's detrimental effects on offspring quality [ 191 ]. One study investigated this prediction by comparing perceptions of the attractiveness of self-resembling own-sex and opposite-sex faces [ 131 ]. Male and female ‘siblings’ of both male and female participants were manufactured using computer-graphic methods detailed in DeBruine et al . [ 163 ]. Participants judged self-resemblance to be more attractive in the context of own-sex faces than in the context of opposite-sex faces. However, there was no such opposite-sex bias when the same faces were judged for averageness. This own-sex bias in preferences for self-resemblance indicates that, while self-resemblance is attractive in an exclusively prosocial (i.e. nonsexual) context, it is less attractive in a potential mating context. Stronger attraction to cues of kinship in own-sex faces than in opposite-sex faces is likely to promote prosocial behaviour towards own-sex kin, while minimizing occurrences of inbreeding with opposite-sex kin. Examples of manipulations of self-similarity can be seen in figure 5 .

Transforms of self-similarity. ( a ) Original picture, ( b ) self-similar and ( c ) self-dissimilar opposite-sex images. Images are made by using the difference between a composite image of the same sex and an individual participant to make faces more similar to the participant. Self-dissimilar faces can be made by applying the same technique but using images other than the participant.

Further evidence for context sensitivity in judgements of self-resembling faces is provided by a study comparing men's and women's preferences for self-resemblance in opposite-sex faces in explicitly prosocial versus sexual contexts [ 132 ]. Participants were shown images of self-resembling opposite-sex faces and asked to judge their trustworthiness (i.e. prosocial context), attractiveness for a short-term relationship (i.e. sexual context) and attractiveness for a long-term relationship (i.e. both prosocial and sexual context). Consistent with both inclusive fitness and inbreeding avoidance theories, self-resemblance increased perceptions of trustworthiness, decreased attractiveness for short-term relationships and had no significant effect on attractiveness for long-term relationships. The fact that self-resemblance in opposite-sex faces was found to be trustworthy, but not attractive in short-term contexts, emphasizes the context-sensitivity of responses to self-resemblance. Importantly, because familiarity increases judgements of both attractiveness and trustworthiness [ 192 ], this pattern of context-sensitivity strongly suggests that responses to self-resemblance do not occur simply because of familiarity alone (i.e. the mere exposure effect [ 193 ]).

Another example of social context influencing face preferences comes from research on interactions among the effects of different facial characteristics on preferences. For example, both behavioural and neurobiological evidence suggest that viewers demonstrate stronger attraction to attractive physical cues in faces (e.g. attractive face shapes or attractive colour) when viewing faces demonstrating positive social interest in the viewer than when viewing faces that appear uninterested in the viewer (e.g. [ 194 , 195 ]). Similarly, behavioural and neurobiological evidence also suggests that viewers demonstrate stronger attraction to cues associated with positive social interest (e.g. eye contact and perceiver-directed smiles) when viewing physically attractive individuals than when viewing relatively unattractive individuals (e.g. [ 196 – 199 ]). Such findings may reflect mechanisms for efficient allocation of mating and/or social effort and can be further modulated by social context. Conway et al . [ 196 ], for example, found that men and women showed stronger preferences for perceiver-directed smiles from opposite-sex than own-sex individuals when judging others' attractiveness, but not when judging their likeability.

(ii) Temporal context

The trade-off theory of women's masculinity preferences proposes that contextual factors that alter the relative importance of the benefits and costs associated with choosing a masculine partner (see §2 c above) will affect the strength of women's preferences for masculine versus feminine men [ 25 , 83 , 92 , 93 , 138 , 200 – 202 ]. For example, women can only make use of the benefit of genetic health for offspring when they are able to conceive and, as discussed above (§3 a (i)), women's preferences for masculine men are modulated by their fertility. Similarly, the putative costs of low investment are much less of a concern in short-term than in long-term relationships and, thus, women may demonstrate stronger masculinity preferences when judging men's attractiveness as possible short-term than long-term partners.

Little et al . [ 93 ] tested this prediction by measuring women's masculinity preferences separately in the context of a short-term and a long-term relationship. Participants interactively manipulated a male face along a continuum from 50 per cent feminized to 50 per cent masculinized until it was ‘closest to the appearance you would find attractive for a short- (or long-) term relationship’. Women who were not using oral contraceptives made this face more masculine in the context of a short-term relationship than in the context of a long-term relationship.

Penton-Voak et al. [ 203 ] also found that women preferred slightly more masculine faces in the context of a short-term relationship than in the context of a long-term relationship, and that this pattern was exaggerated in the least attractive participants (i.e. women with high waist–hip ratios or low other-rated facial attractiveness). One potential explanation for this pattern of preference is that attractive women are better able to compete for, retain or replace high-quality, masculine partners and, therefore, do not show as large a shift in their preferences between short-term and long-term contexts. Indeed, several studies have shown that more attractive women show stronger preferences for masculine faces and voices (reviewed above in §3 a (ii)).

The effects of temporal context on judgements of attractiveness are not limited to faces. Women prefer lower pitched male voices in the context of a short-term relationship than in the context of a long-term relationship [ 143 ]. This same study also found that the effect of relationship context was greatest when women were in the fertile phase of the menstrual cycle, a finding that is consistent with research on cyclic shifts in preferences for facial masculinity [ 138 ].

(iii) Environmental context

A strong theoretical prediction of the trade-off account of variability in women's preferences for masculine men is that women in environments where poor health is particularly harmful to survival (e.g. environments with high prevalence of pathogens and inaccessible or poor healthcare) will demonstrate stronger preferences for cues of health [ 25 , 83 , 92 , 93 , 138 , 200 – 202 ]. Regional differences in pathogen prevalence have been shown to be positively correlated with the importance placed on physical beauty and health [ 204 , 205 ].

DeBruine et al. [ 206 ] investigated the relationship between environmental cues of the importance of health and women's preferences for masculinity in a sample of 30 countries. Health statistics from the World Health Organization were used to compute a ‘national health index’ (NHI), which was negatively correlated ( r = −0.62) with women's average masculinity preferences for each country. This relationship remained significant, even when controlling for regional variation in wealth and women's mating strategies (i.e. whether women tended to pursue more short-term or long-term relationships; [ 207 ]).

Brooks et al. [ 208 ] have re-analysed these data and suggested that regional variation in women's masculinity preferences may be better explained by regional variation in male–male violence. Masculine-faced men may be favoured under such conditions, for example, as they may be better able to compete for resources. A further study of US states, in contrast, has shown that environmental health factors, and not indices of male–male violence such as homicide rates, predicts regional variation in women's masculinity preferences [ 209 ]. Health, wealth and male–male violence are, of course, inter-related. While it is ultimately possible that health, wealth and male–male violence may all individually contribute to variation in preference, it is important to note that all of these analyses show that regional variation in women's masculinity preferences occurs in ways that are highly consistent with trade-off theories of sexual selection.

The availability of resources in an environment may also influence face preferences. In low-resource environments, the resources to raise a child may be scarce or difficult to acquire and a preference for an investing partner be adaptive. In contrast, in higher resource environments, there may be little gain in terms of offspring survival and reproduction by the additional effort of a second parent and a preference for ‘good genes’ may be a better strategy [ 210 , 211 ]. To test these ideas, Little et al. [ 212 ] tested men's and women's preferences for masculinity/femininity in two contexts: a harsh environment with few resources and a safe environment with plentiful resources. Both men and women decreased their preferences for high quality mates for long-term relationships in the context of a harsh environment. For example, women were relatively more attracted to feminine faced men for long-term relationships in low resource environments, suggesting that women value potential investment from these men more than the higher dominance/health of masculine faced men under these conditions. This is consistent with the logic of trading genetic quality for commitment and investment in environments where resources are scarce.

(c) Visual experience

Individuals are confronted with a myriad of faces and social interactions every day. Research has shown that such experience leads to changes in preferences for faces. In the following section, we discuss two aspects of visual experience examining: (i) how exposure can impact on preferences and (ii) how observing the choices of others may affect our preferences.

(i) Exposure

Familiarity is a powerful determinant of attraction. For many types of stimuli, including faces, exposure increases attraction even when the exposure is unconscious [ 213 – 215 ]. Structural features of the face must be stored and represented in order to determine familiarity. As noted earlier, one idea for why averageness in faces is attractive comes from a link with familiarity—as average faces appear familiar this could positively affect their attractiveness [ 60 , 62 ].

Familiarity, when not paired with aversive stimuli, is thought to be rewarding [ 214 ], and indeed there are obvious benefits to avoiding the unfamiliar. This can then help explain why exposure may cause increases in preference. There may, however, be more to increasing face preference than simple exposure. For example, recent studies have demonstrated that the nature of association (positive or negative) can affect face preferences, with positive experiences leading to increased attraction and negative experiences to decreased attraction [ 216 ]. Moreover, these effects of valenced exposure are not bound solely to the specific individuals who were encountered and generalize to judgements of novel, physically similar individuals [ 216 ].

Familiarity with parental traits has been implicated in human preferences. The phenomenon of imprinting, whereby individuals are attracted to parental traits, is well-studied in non-human animals [ 217 , 218 ] and there is increasing evidence for similar effects in humans. Following studies of facial similarity, judges have been shown to correctly match wives to their mother-in-law at a significantly higher rate than expected by chance and that wife–mother-in-law similarity is higher than similarity between husbands and their wives [ 219 ]. Such effects are also seen in adopted daughters, controlling for any potential genetic effects, with significant facial resemblance between daughter's husband and her adoptive father [ 220 ]. Other studies have shown that, for hair and eye colour, the best predictors of partner traits are the opposite-sex parent's colour traits [ 128 ] and that individuals are attracted to age in faces consistent with the age of their parents when they were born [ 221 ]. It is worth noting that at least in one study, effects were seen mainly for the opposite-sex parent [ 128 ], which may indicate a more complex mechanism than simple exposure. Another line of argument suggesting imprinting-like effects appear not simply to reflect exposure comes from studies that have shown effects to be dependent on the quality of the relationship to the parent [ 220 , 222 ]. For example, daughters who report that they received greater emotional support from their adoptive fathers are more likely to choose mates who are similar to their father than individuals who report their father provided less emotional support [ 220 ]. Similarly, women who rate their childhood relationships with their father positively show stronger attraction to face proportions similar to their father's face than women who rate their relationships less well [ 222 ]. Imprinting-like effects then appear more complicated than simple exposure being directed more to one parent than the other and showing dependence on the relationship with that parent.

Imprinting-like effects may lead to positive assortative mating (pairing with similar partners), at least for long-term relationships, and this may have benefits in terms of keeping adaptive suites of genes together [ 223 ] or increasing behaviour compatibility [ 224 ]. There is certainly evidence that couples resemble each other facially [ 225 , 226 ]. While there are costs to inbreeding, as discussed earlier, a certain amount of genetic similarity can be beneficial—so-called ‘optimal-outbreeding’ [ 227 ]. Potentially then, a system that learns about known individuals and increases attraction to their face traits could be adaptive.

Both familiarity and imprinting posit that exposure affects attractiveness. In recent years, exposure has been thought to have specific effects on our representations of faces via visual adaptation. We are unlikely to have an inbuilt average face and what is average must be calculated from experience. For each class of stimuli, the human visual system encounters may develop an individual representation, or prototype, made up of an average of the characteristics of all the different stimuli of that type that have been seen [ 228 – 232 ]. Computer modelling has revealed that algorithms trained to discriminate different stimuli produce stronger responses to stimuli that represent the average of the training set, even though this average was not previously encountered [ 228 , 230 ]. These findings have been interpreted as evidence that prototype formation is a property of learning to recognize different stimuli as members of a class [ 228 , 230 ].

Studies on category learning have a long history (e.g. [ 233 ]). Learning studies examine how categorical perception develops using abstract stimuli. In classic studies, it has been shown that exposure to different dot patterns with particular configurations results in abstraction so that the average of each of the patterns, while never previously seen, is recognized as belonging to the set of patterns from which it was derived [ 233 ].

Faces have been the focus of much research regarding recognition and prototype formation. While it has been proposed that faces may be coded as veridical representations of individuals or exemplars [ 232 ], recent neuroimaging and single-cell recording studies have supported a prototype-referenced model of face coding [ 229 , 231 ]. Exposure to faces biases subsequent perceptions of novel faces, causing faces similar to those initially viewed to appear more prototypical than they would otherwise be perceived as, presumably, a prototype or population of exemplars becomes updated [ 234 – 239 ]. For example, adaptation to faces with contracted features causes novel faces with contracted features to be perceived as more normal than prior to this exposure [ 235 , 239 , 240 ]. Analogous visual after-effects have been observed following exposure to faces varying in identity [ 234 , 236 ], ethnicity [ 237 ], sex [ 235 , 237 , 241 ], expression [ 237 ], mouth shapes associated with different spoken sounds [ 242 ] and masculinity/femininity [ 192 , 243 ]. Such after-effects are thought to reflect changes in the responses of neural mechanisms underlying face processing [ 235 , 238 – 240 ].

These studies may then shed light on how the brain builds an average representation to which the other faces can be compared. Importantly, exposure in the manner described above also influences attractiveness judgements. After exposure to faces possessing certain traits, these traits come to be preferred [ 192 , 240 , 243 , 244 ]. For example, if exposed to faces that look more like one identity, then new faces that resemble that identity are found more attractive than if exposed to the opposite set of face traits. A similar effect has also been observed for judgements of the trustworthiness of faces [ 192 ]. Adaptation then reflects the rapid updating of face norms and can therefore be tied both to the effects of familiarity and imprinting-like effects.

(ii) Social learning

We have dealt briefly with some aspects of simple experience on preferences above, but, of course, humans are highly social and much human experience is of what other humans do. Humans can therefore learn about attractiveness from the behaviour of those around them: social learning of preference. We have recently reviewed social learning in human face preferences [ 245 ], and so present a brief overview here.

Individuals often learn from others and selection for social learning mechanisms may occur when there are costs to acquiring accurate behavioural information via individual learning [ 246 ]. Social learning can be adaptive if it allows an individual to assess potential mates more quickly and efficiently than through individual trial and error or allows an individual to use another's expertise. Mate choice copying has been observed among females in a number of different non-human species [ 247 – 250 ], including fish [ 251 – 254 ] and bird species [ 255 – 257 ]. Such studies have generally shown that when females observe another female (the model) to be paired with one of the two males (the targets), they are subsequently more likely to prefer the target male they had seen paired with the model over the male that was not paired with the model.

Inspired by work on non-human species, recent research also suggests that social learning may influence human mate preferences. While some research has shown that the presence of wedding rings on men did not increase women's preferences for those men [ 258 ], other studies have found that images of men labelled as married were more attractive than those labelled as single [ 259 ] and that women rate men as more desirable when they are shown surrounded by women than when they are shown alone or with other men [ 260 ]. Another study has shown that women prefer pictures of men that had been previously seen paired with images of other women who were looking at the face with smiling (i.e. positive) expressions compared with pictures of men who had been seen paired with images of women with neutral (i.e. relatively negative) expressions [ 261 ]. Women therefore do appear to mimic the attitude of other women to particular men.

Alongside partnership status, simple presence, and expressions of attitude towards the male, the physical traits of the observed model may also play a role in the social transmission of preference. Previous studies have shown that men's and women's attractiveness judgements are influenced by the apparent choice of attractive members of the same sex. Sigall & Landy [ 262 ] used real individuals to show that positive characteristics are attributed more frequently to men who are paired with attractive rather than unattractive women. In this way, they show that an attractive partner may ‘radiate beauty’. Such a phenomenon suggests a more sophisticated form of mate-choice copying, whereby women can use the attractiveness of a partner that a man can acquire in order to judge the man's own attractiveness. Another study using images that were presented with a fictitious partner has shown that both men and women find a face paired with an attractive partner to be more attractive than one paired with an unattractive partner for a long-term but not a short-term relationship [ 263 ]. Effects specific to long-term preferences in humans suggest that social information is being used to infer non-physical traits that make a target a good long-term partner, such as resources or intelligence, which may be difficult to determine from physical appearance alone.

4. Summary and conclusions

Being more or less attractive has important social consequences and people do generally agree on who is and who is not attractive. Beauty is not just a simple social construct—attractiveness appears to be ingrained in our biology. While some aspects of face perception might be innate, other aspects are clearly influenced by experience; it seems unlikely that individuals are born with a representation of what a perfect partner looks like.

Structural and other aspects of human facial appearance are linked to preferences (§2). If a trait reliably advertises some benefit to the perceiver, then we would expect individuals in a population to find that trait attractive. It is clear that individual differences in preferences for some traits will prove adaptive and so are consistent with evolutionary theory. We document several potentially adaptive individual differences in human face preferences as well as other factors that may lead to variable preferences (§3). Research on human facial attractiveness has benefited greatly from an evolutionary/biological perspective, both in terms of documenting what traits are likely to be important and in predicting individual variation. Work on facial attractiveness is also integrative, combining theories and methods from behavioural ecology, cognition, cross-cultural research and social psychology.

Acknowledgements

Anthony Little is supported by a Royal Society University Research Fellowship.

One contribution of 10 to a Theme Issue ‘ Face perception: social, neuropsychological and comparative perspectives ’.