Evolutionary psychology controversy
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The purpose of this article is to outline the various criticisms of evolutionary psychology, as well as counterarguments to these criticisms.
The application of evolutionary theory to animal behavior is generally uncontroversial. However, adaptationist approaches to human psychology are contentious, with critics questioning the scientific nature of evolutionary psychology, and with more minor debates within the field itself. The history of debate from the evolutionary psychology perspective is covered in detail in books by Segerstråle (2000) and Alcock (2001)); also see a recent overview of EP with rebuttals to critics in Tooby, J. & Cosmides, L. (2005). Conceptual foundations of evolutionary psychology. Full text, as well as Controversies surrounding evolutionary psychology by Edward H. Hagen, both in D. M. Buss (Ed.), The Handbook of Evolutionary Psychology (Hoboken, NJ: Wiley).
The debates regarding the validity of evolutionary psychology have been regarded as occasionally quite vicious, with a strong ad hominem component. Some have suggested that the controversies would constitute a quiet debate over subtleties if the participants were less prone to caricaturing their opponents. (Also see the Biopsychiatry controversy which may have some overlap with this topic.)
Criticisms of Method
The "Environment of Evolutionary Adaptedness"
Evolutionary psychologists argue that they use knowledge of the environment of evolutionary adaptedness to generate hypotheses regarding possible psychological adaptations, and subsequently, these hypotheses can be tested and evaluated against the empirical evidence.
Critics of evolutionary psychology allege that because little is known about the Pleistocene, the evolutionary context in which humans developed (including population size, structure, lifestyle, eating habits, habitat, and more), there is little basis on which evolutionary psychology can operate.
Evolutionary psychologists state that their research is confined to certainties about the past, such as pregnancies only occurring in women, and that humans lived in groups. They posit that there are many environmental features that we can be sure played a part in our species' evolutionary history. They argue that our hunter-gatherer ancestors most certainly dealt with predators and prey, food acquisition and sharing, mate choice, child rearing, interpersonal aggression, interpersonal assistance, diseases and a host of other fairly predictable challenges that constituted significant selection pressures.
There exists debate within evolutionary psychology about the nature of the EEA. Many evolutionary psychologists contend that many aspects of the EEA were rather variable. This argument is used to support the notion that the mind consists of not only domain-specific psychological mechanisms but of more domain-general ones as well (that deal with environmental novelty).
Critics assert that many hypotheses put forward to explain the adaptive nature of human behavioural traits are "Just So stories"; neat adaptive explanations for the evolution of given traits that do not rest on any evidence beyond their own internal logic. They allege that evolutionary psychology can predict many, or even all, behaviours for a given situation, including contradictory ones. Therefore many human behaviours will always fit some hypotheses.
For example, kin selection predicts that humans will be altruistic toward relatives in proportion to their relatedness, while reciprocal altruism predicts that we will be altruistic toward people from whom we can expect altruism in the future (but not strangers). However, altruism towards a complete stranger fits the handicap principle. A story of any complexity can be constructed to fit any behaviour, but, critics assert, nothing distinguishes one story from another experimentally.
Defenders of evolutionary psychology suggest that the term "just so story" is a derogatory way of describing alternative hypotheses which need empirical evaluation. Furthermore there is no known scientific mechanism which can explain human behaviour besides natural selection.
"Those who have a professional knowledge of evolutionary biology know that it is not possible to cook up after the fact explanations of just any trait. There are important constraints on evolutionary explanation. More to the point, every decent evolutionary explanation has testable predictions about the design of the trait. For example, the hypothesis that pregnancy sickness is a byproduct of prenatal hormones predicts different patterns of food aversions than the hypothesis that it is an adaptation that evolved to protect the fetus from pathogens and plant toxins in food at the point in embryogenesis when the fetus is most vulnerable – during the first trimester. Evolutionary hypotheses – whether generated to discover a new trait or to explain one that is already known – carry predictions about the nature of that trait. The alternative – having no hypothesis about adaptive function – carries no predictions whatsoever. So which is the more constrained and sober scientific approach?"
In his review article Discovery and Confirmation in Evolutionary Psychology (in The Oxford Handbook of Philosophy of Psychology) Edouard Machery concludes:
"Evolutionary psychology remains a very controversial approach in psychology, maybe because skeptics sometimes have little first-hand knowledge of this field, maybe because the research done by evolutionary psychologists is of uneven quality. However, there is little reason to endorse a principled skepticism toward evolutionary psychology: Although clearly fallible, the discovery heuristics and the strategies of confirmation used by evolutionary psychologists are on a firm grounding."
Evolutionary psychologists claim that many traits have been shown to be universal in humans, however many critics have pointed out that many traits considered universal at some stage or another by evolutionary psychologists and sociobiologists often turn out to be dependant on cultural and particular historical circumstances. Critics allege that evolutionary psychologists tend to assume that their own current cultural context represents a universal human nature, for example, in a review of Steven Pinker's book on evolutionary psychology (The Blank Slate), Louis Menand wrote: "In general, the views that Pinker derives from "the new sciences of human nature" are mainstream Clinton-era views: incarceration is regrettable but necessary; sexism is unacceptable, but men and women will always have different attitudes toward sex; dialogue is preferable to threats of force in defusing ethnic and nationalist conflicts; most group stereotypes are roughly correct, but we should never judge an individual by group stereotypes; rectitude is all very well, but "noble guys tend to finish last"; and so on.".
No one would suggest that physiology or evolutionary physiology is ethnocentric because it attempts to identify "human body nature." EP researchers actually focus on commonalities between people of different cultures to help to identify their common "human psychological nature." Ironically, it is not a focus on local behavioral variation (which may sometimes be considered ethnocentric) that interests evolutionary psychologists; rather their focus is to find underlying psychological commonalities between people from various cultures. David Buss, David P. Schmitt, and other evolutionary psychologists are noted for cross-cultural research projects that have gathered massive datasets, with tens of thousands of research participants from around the world, to test EP adaptationist hypothesizes. See the above researchers' websites for publications regarding this.
Evolutionary Psychology is grounded on the theory that fundamentally our psychology is based on biology, the composition of our brains. This is a form of reductionism, a research philosophy according to which the nature of complex things can be understood in terms of simpler or more fundamental things (i.e. reduced). Reductionism as applied to consciousness and the brain comes in various forms. Evolutionary Psychology is not solely committed to a reductionist outlook, being potentially compatible with Supervenience, Interactionism, Epiphenomenalism and both Token and Type physicalism, for example.
Critics allege that a reductionist analysis of the relationship between genes and behaviour results in a flawed research program and a restricted interpretation of the evidence, creating problems for the creation of models attempting to explain behaviour. For example, Lewontin, Rose & Kamin advocate a "dialectical" interpretation of behaviour that opposes the hierarchical reductionism given by Dawkins, in which "it is not just that wholes are more than the sum of their parts, it is that parts become qualitatively new by being parts of the whole." They argue that reductionist explanations will cause the researcher to miss dialectical ones.
The evolutionary biologist Richard Dawkins has alleged that reductionism is only invoked because EP is a controversial field in itself, Dawkins writes: "'reductionism', like sin, is one of those things only mentioned by people who are against it." The Blind Watchmaker, 1986 p.13. (Here Dawkins makes a distinction between "direct" and "hierarchical" scientific reductionism: organisms can be described in terms of DNA, DNA in terms of atoms, atoms in terms of sub-atomic particles etc; but knowledge of sub-atomic particles will not directly explain animal or human behavior, nevertheless, one can make adequate explanations and predictions at higher levels.)
Criticisms of inherited/"modular" psychological traits
Behavior and inheritance
Evolutionary psychology, human behavioral ecology and sociobiology are based on the fundamental premise that particular behavioral traits are hereditary. No adaptive evolution can occur unless a trait is genetic and suitable genetic variation exists within that trait for selection to act. Furthermore, for those behavioural traits that do have a genetic basis, behaviour (along with certain parts of the immune system) is the most rapidly evolving set of traits. The presence or absence of inherited behavioural traits represents an ongoing debate within psychology.
Most psychologists believe that there is substantial empirical evidence to suggest that there are genetic predispositions for many emotional, cognitive and behavioral traits (the discipline of behavioral genetics is devoted to such studies). Much of this research is based on twin and adoption studies, as well as genetic comparisons between people with an identified trait (e.g., schizophrenia) and those without it.
Searches for genetic variation in traits are complicated by the fact that if a trait is beneficial enough and has spread throughout a population, there will be no more genetic variability about that trait because all members of the population will possess the genes for that trait. As a non-behavioural example of this principle, one's number of limbs at birth is presumably affected by one's genes, but there is not likely to be much genetic variation among humans in the number of limbs because the genes responsible have become fixed. Thus, most of the phenotypic variation in this trait (i.e. what is observed) will not be the result of genetic variation and will instead be the result of differing environments (e.g. presence/absence of thalidomide in the womb), despite the importance of genes in determining limb number at birth. Similarly, behavioral traits that are very adaptive (including conditional traits and "if-then" decision rules) will actually show very low genetic variability, simply because the genetic variation has been used up and the trait has gone to fixation in the population.
The Reification Fallacy
Some critics argue that evolutionary psychology regularly commits the reification fallacy; where abstract behaviors are treated as real "objects" within the mind, when there is no sufficient evidence to suppose that such behaviors represent true discreet "traits". The classic example is of IQ; an IQ score is a statistical principal component (dubbed g) taken from the scores of several artificial mental tests, and many researchers early in the 20th century came to treat this g as a genuine thing within the brain.
Psychologists (with the exception of behaviorists) respond that hypothesized psychological traits that cannot be measured directly (personality traits, IQ, etc.) may be described as psychological "constructs." Psychological constructs are theoretical hypotheses about how people differ, or how components of the mind work. The degree to which a construct is accepted in the scientific community depends on empirical research that demonstrate that a construct has "construct validity" (especially, predictive validity). Researchers assume that when people differ on a psychological construct, there are indeed underlying neurological differences between them (e.g., between the brains of introverts and extroverts). Other sciences use constructs as well (in physics: atomic theory, string theory, etc.). Thus, if constructs are properly understood, the "reification fallacy" is not a fallacy at all -- it is one part of theory creation and evaluation in normal science.
Problem-specific Modularity vs. General Purpose Problem Solvers
Some commentators, like philosopher David Buller, agree with the general argument that the human mind has evolved over time but disagree with the specific claims evolutionary psychologists make. Buller has argued that the contention that the mind consists of thousands of modules, including sexually dimorphic jealousy and parental investment modules, are unsupported by the available empirical evidence.  (But see Daly and Wilson's response to Buller.)
An alternative to the "mental module" view of how human minds evolved is offered by cognitive psychologist Merlin Donald. He argues that over evolutionary time the mind has gained adaptive advantage from a general problem solver. Donald articulates this view in his book "A Mind So Rare: The Evolution of Human Consciousness" .
See  Daly and Wilson's response to Buller's criticism above, as well as Delton, Robertson, Kenrick (2006) The Mating Game Isn’t Over: A Reply to Buller’s Critique of the Evolutionary Psychology of Mating. , and Miele (2006) Evolutionary Psychology is Here to Stay: A Response to Buller. 
With respect to general purpose problem solvers, see Barkow, Cosmides, and Tooby (1992) The Adapted Mind: Evolutionary Psychology and The Generation of Culture for their argument that a purely general problem solving mechanism is impossible to build due to the frame problem.
Criticisms of adaptationism
Critics assert that evolutionary psychology has trouble developing research that can distinguish between environmental and cultural explanation and adaptive evolutionary explanations. Some studies have been criticized for their tendency to attribute to evolutionary processes elements of human cognition that may be attributable to social processes (e.g. preference for particular physical features in mates), cultural artifacts (e.g. patriarchy and the roles of women in society), or dialectical considerations (e.g. behaviours in which biology interacts with society, as when a biologically determined skin colour determines how one is treated). Evolutionary psychologists are frequently criticized for ignoring the vast bodies of literature in psychology, philosophy, politics and social studies. Both sides of the debate stress that statements such as "biology vs. environment" and "genes vs. culture" amount to false dichotomies, and outspoken critics of sociobiology such as Richard Lewontin, Steven Rose and Leon Kamin helped to popularise a "dialectical" approach to questions of human behaviour, where biology and environment interact in complex ways to produce what we see.
Evolutionary psychologists respond that their discipline is not primarily concerned with explaining the behavior of specific individuals, but rather broad categories of human behaviors across societies and cultures. It is the search for species-wide psychological adaptations (or "human nature") that distinguishes evolutionary psychology from purely cultural or social explanations. In addition, EP fully accepts nature-nurture interactionism.
Adaptive explanations vs. other evolutionary mechanisms
Critics assert that evolutionary psychology fails to produce experiments that disentangle potential adaptive bases of behavior from other evolutionary influences. One premise of evolutionary psychology that distinguishes it from other theories of human behavior is that some mental traits are thought to be adaptive.
Critics point out that within evolutionary biology there are many other non-adaptive pathways along which evolution can move to produce the behaviors seen in humans today. Natural selection is not the only evolutionary process that can change gene frequencies and produce novel traits. Genetic drift refers to random effects resulting from chance variation in the genes, environment, or development. Evolutionary by-products are traits that were not specially designed for an adaptive function, although they may also be species-typical and may also confer benefits on the organism. A "spandrel" is a term coined by Gould and Lewontin (1979a) for traits which confer no adaptive advantage to an organism, but are 'carried along' by an adaptive trait. Gould advocates the hypothesis that cognition in humans came about as a spandrel: "Natural selection made the human brain big, but most of our mental properties and potentials may be spandrels - that is, nonadaptive side consequences of building a device with such structural complexity".
Once a trait acquired by some other mechanism confers an adaptive advantage, as evolutionary psychologists claim that many of our "mental properties and potentials" do, it may be open to further selection as an "exaptation". Critics allege that the adaptive (and exaptive) significance of mental traits studied by evolutionary psychologists has not been shown, and that selection has not necessarily guided the appearance of such traits.
Evolutionary psychologists suggest that critics mischaracterize their field, and that their empirical research is designed to help identify which psychological traits are likely to adaptations, and which are not. For example, see Adaptations, Exaptations and Spandrels, by Buss, Haselton, Shackelford, Bleske and Wakefield. Also see How can we identify psychological adaptations? by Edward H. Hagen, Institute for Theoretical Biology, Berlin.
Political and Ethical Issues
That human psychology may be determined by our biology, which is shaped by our evolutionary past, is an important idea for those involved in ethics. The implications are as broad and varied as the field of ethics itself.
Some believe that Evolutionary Psychology describes factors which limit our free will, in that it can be seen to imply that we behave in ways in which we are ‘naturally inclined’. J. Mizzoni wrote “There are some moral philosophers (such as Thomas Nagel) who believe that evolutionary considerations are irrelevant to a full understanding of the foundations of ethics. Other moral philosophers (such as J. L. Mackie) tell quite a different story. They hold that the admission of the evolutionary origins of human beings compels us to concede that there are no foundations for ethics.”Ruse's Darwinian ethics and Moral Realism:
Critics of this ethical view point out that whether or not a behavioral trait is inherited does not affect whether it can be changed by ones culture or independent choice, and that evolutionary psychology could be discarded in moral and political discussions regardless of whether it is true or not.
The concept of "free will" is more of a philosophic issue than a scientific one, given that it is difficult to experimentally conceptualize or to empirically test. It is also largely a semantic house of mirrors: we feel free (have "free will") when we have the capacity to choose. However, do we have the capacity to choose what we want to choose? (And, if so, can we choose what we want to want to choose, and so on...) EP, as does psychological science in general, operates under the assumption that human behavior has causal roots. Our desires and wants, and our choices, are a complex interaction of biology and environment; we can "feel free" while our behavior is determined. Daniel C. Dennett's (2003) book "Freedom Evolves" is a good starting place for further exploration of this topic.
"Is" and "Ought"
Evolutionary Psychology is not promoted as a theory of ethics, merely stating what is, not what ought to be, but many critics have alleged that evolutionary psychology and sociobiology are nothing more than political justifications for the "status quo." Evolutionary psychologists have long been accused of conflating "is" and "ought", and evolutionary psychology has been used to argue against social change (because the way things are now has been evolved and adapted), and to argue against social justice (e.g. the claim that the rich are only rich because they've inherited greater abilities, so programs to raise the standards of the poor are doomed to fail).
See also: Ethics and evolutionary psychology
Contrary to critics, EP does not use the naturalistic fallacy nor the moralistic fallacy. Medical scientists who study causal factors related to the transmission of malaria are not endorsing malaria as a good thing. Neither are EP scientists who study the ultimate (evolutionary) causes of, say, homicide or infidelity, endorsing these phenomena. To the contrary, an accurate understanding of causal factors is needed if one wishes to reduce the incidence of either malaria or violence.
- For an outline of the current state of knowledge in this area, see: Mithen, Steven. After The Ice: A Global Human History 20000-5000 BC. Harvard Uni. Press, 2004).
- Menand, L. (2002) "What Comes Naturally", The New Yorker, 22nd November 2002; available online at http://www.hereinstead.com/sys-tmpl/bmenadonpinker/
- See Chapter 10 of "Biology, Ideology and Human Behavior: Not In Our Genes" (1984) by Lewontin, Rose & Kamin for a discussion of these issues.
- Lewontin, R.C. "It Ain't Necessarily So"
- Gould, S.J. (1981) "The Mismeasure of Man"
- Lewontin, Rose & Kamin (1984) "Biology, Ideology and Human Nature: Not In Our Genes", Chapter 10
- Quote from Stephen Jay Gould, The Pleasures of Pluralism, p.11
- Lewontin, R.C., Rose. S & Kamin, L (1984) Biology, Ideology and Human Nature: Not In Our Genes
- Kohn, A. (1990) The Brighter Side of Human Nature"
- Lewontin, R.C., Rose. S & Kamin, L (1984) Biology, Ideology and Human Nature: Not In Our Genes