Criticism of evolutionary psychology

Evolutionary psychology has generated substantial controversy and criticism. The criticism – which has been most forceful from proponents of constructivist, postmodernist and poststructuralist schools of thought – includes but is not limited to: disputes about the testability of evolutionary hypotheses, alternatives to some of the cognitive assumptions (such as massive modularity) frequently employed in evolutionary psychology, alleged vagueness stemming from evolutionary assumptions (such as uncertainty about the environment of evolutionary adaptation), differing stress on the importance of non-genetic and non-adaptive explanations, and political and ethical issues.^[1]

While evolutionary psychology has been accused of straw man evidence, ideologically rather than scientifically motivated, evolutionary psychologists respond by arguing that these criticisms are also straw men, are based on an incorrect nature versus nurture dichotomy, or are based on misunderstandings of the discipline.^{[2][3][4][5][6][7][8]}

History

The history of the debate from the critics' perspective is detailed by Gannon (2002).^[9] Critics of evolutionary psychology include the philosophers of science David Buller author of Adapting Minds,^[10] Robert C. Richardson author of Evolutionary Psychology as Maladapted Psychology,^[11] and Brendan Wallace, author of Getting Darwin Wrong: Why Evolutionary Psychology Won't Work. Other critics include neurobiologists like Steven Rose who edited "Alas, Poor Darwin: Arguments against Evolutionary Psychology", and biological anthropologists like Jonathan Marks and social anthropologists like Tim Ingold and Marshall Sahlins.^[10][12][13]

The evolutionary psychology response to critics has been covered in books by Segerstråle (2000), Defenders of the Truth: The Battle for Science in the Sociobiology Debate and Beyond,^[14] Barkow (2005), Missing the Revolution: Darwinism for Social Scientists,^[15] and Alcock (2001), The Triumph of Sociobiology.^[4] See also: rebuttals to critics in Confer, et al. (2010),^[16] Tooby and Cosmides (2005),^[17] and Hagen (2005).^[18]

Massive modularity

Evolutionary psychologists have postulated that the mind is composed of cognitive modules specialized to perform specific tasks. Evolutionary psychologists have theorized that these specialized modules enabled our ancestors to react quickly and effectively to environmental challenges. As a result, domain-specific modules would have been selected for, whereas broad general-purpose cognitive mechanisms that worked more slowly would have been eliminated in the course of evolution.^[19][20]

A number of cognitive scientists have criticized the modularity hypothesis, citing neurological evidence of brain plasticity and changes in neural networks in response to environmental stimuli and personal experiences.^[19][20] Steven Quartz and Terry Sejnowski, for example, have argued that the view of the brain as a collection of specialized circuits, each chosen by natural selection and built according to a "genetic blueprint", is contradicted by evidence that cortical development is flexible and that areas of the brain can take on different functions.^[21] Neurobiological research does not support the assumption by evolutionary psychologists that higher-level systems in the neocortex responsible for complex functions are massively modular.^[22][23] Peters (2013) cites neurological research showing that higher-order neocortical areas can become functionally specialized by way of synaptic plasticity and the experience-dependent changes that take place at the synapse during learning and memory. As a result of experience and learning processes the developed brain can look modular although it is not necessarily innately modular.^[22] However, Klasios (2014) responds to Peters' critique.^[24]

Another criticism is that there is little empirical support in favor of the domain-specific theory.^[25][26] Leading evolutionary psychologists Leda Cosmides and John Tooby have found that performance on the selection task is content-dependent: People find it easier to detect violations of "if-then” rules when the rules can be interpreted as cheating on a social contract. From this Cosmides and Tooby and other evolutionary psychologists concluded that the mind consisted of domain-specific, context-sensitive modules (including a cheater-detection module).^[26] Critics have suggested that Cosmides and Tooby use untested evolutionary assumptions to eliminate rival reasoning theories and that their conclusions contain inferential errors.^[26][27] Davies et al., for example, have argued that Cosmides and Tooby did not succeed in eliminating the general-purpose theory because the adapted Wason selection task they used tested only one specific aspect of deductive reasoning and failed to examine other general-purpose reasoning mechanisms (e.g., reasoning based on syllogistic logic, predicate logic, modal logic, and inductive logic etc.).^[26] Furthermore, Cosmides and Tooby use rules that incorrectly represent genuine social exchange situations. Specifically, they posit that someone who received a benefit and does not pay the cost is cheating. However, in real-life social exchange situations people can benefit and not pay without cheating (as in the case of receiving gifts or benefiting from charity).^[26]

Some critics have suggested that our genes cannot hold the information to encode the brain and all its assumed modules.^[22] Humans share a significant portion of their genome with other species and have corresponding DNA sequences so that the remaining genes must contain instructions for building specialized circuits that are absent in other mammals.^[22][28][29]

One controversy concerns the particular modularity of mind theory used in evolutionary psychology (massive modularity). Critics argue in favor of other theories.^[30][31]

Fear and phobias as innate or learned

Critics have questioned the proposed innateness of certain phobias, such as fear of snakes.^[32] Recent evidence, however, suggests that Japanese macaques, and presumably other primates, have a snake-detection brain module—neurons in the preferential medial and dorsolateral pulvinar—that respond very rapidly to images of snakes, even without any prior exposure to snakes.^[33][34]

Environment of evolutionary adaptedness

One method employed by evolutionary psychologists is using knowledge of the environment of evolutionary adaptedness to generate hypotheses regarding possible psychological adaptations.

Part of the critique of the scientific basis of evolutionary psychology is of the concept of the environment of evolutionary adaptation. Evolutionary psychology often assumes that human evolution occurred in a uniform environment, and critics suggest that we know so little about the environment (or probably multiple environments) in which homo sapiens evolved, that explaining specific traits as an adaption to that environment becomes highly speculative.^[35]

The evolutionary psychologists John Tooby and Leda Cosmides state that research is confined to certainties about the past, such as pregnancies only occurring in women, and that humans lived in groups. They argue that there are many environmental features that are known regarding our species' evolutionary history. They argue that our hunter-gatherer ancestors 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. Knowledge also include things such as nomadic, kin-based lifestyle in small groups, long life for mammals, low fertility for mammals, long female pregnancy and lactation, cooperative hunting and aggression, tool use, and sexual division of labor.^[36]

Empirical evidence

Some hypotheses that certain psychological traits are evolved adaptations have not been empirically corroborated.^[37]

Testability

A frequent criticism of evolutionary psychology is that its hypotheses are difficult or impossible to test, challenging its status as an empirical science. As an example, critics point out that many current traits likely evolved to serve different functions from those they do now, confounding attempts to make backward inferences into history.^[43] Evolutionary psychologists acknowledge the difficulty of testing their hypotheses but assert it is nevertheless possible.^[44]

Critics argue 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.^[45] 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. Noam Chomsky argued:

"You find that people cooperate, you say, 'Yeah, that contributes to their genes' perpetuating.' You find that they fight, you say, ‘Sure, that’s obvious, because it means that their genes perpetuate and not somebody else's. In fact, just about anything you find, you can make up some story for it."^[46][47]

Leda Cosmides argued in an interview:

"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?"

A 2010 review article by evolutionary psychologists describes how an evolutionary theory may be empirically tested. A hypothesis is made about the evolutionary cause of a psychological phenomenon or phenomena. Then the researcher makes predictions that can be tested. This involves predicting that the evolutionary cause will have caused other effects than the ones already discovered and known. Then these predictions are tested. The authors argue numerous evolutionary theories have been tested in this way and confirmed or falsified.^[48] Buller (2005) makes the point that the entire field of evolutionary psychology is never confirmed or falsified; only specific hypotheses, motivated by the general assumptions of evolutionary psychology, are testable. Accordingly, he views evolutionary psychology as a paradigm rather than a theory, and attributes this view to prominent evolutionary psychologists including Cosmides, Tooby, Buss, and Pinker.^[49]

In his review article "Discovery and Confirmation in Evolutionary Psychology" (in The Oxford Handbook of Philosophy of Psychology) Edouard Machery concludes:^[50]

"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."

Ethnocentrism

One aspect of evolutionary psychology is finding traits that have been shown to be universal in humans. Many critics have pointed out that many traits considered universal at some stage or another by evolutionary psychologists often turn out to be dependent on cultural and particular historical circumstances.^[51][52][53] Critics allege that evolutionary psychologists tend to assume that their own current cultural context represents a universal human nature. For example, anthropologist Susan McKinnon argues that evolutionary theories of kinship rest on ethnocentric presuppositions. Evolutionary psychologists assert that the degree of genetic relatedness determines the extent of kinship (e.g., solidarity, nurturance, and altruism) because in order to maximize their own reproductive success, people "invest" only in their own genetic children or closely related kin. Steven Pinker, for instance, stated "You're either someone's mother or you aren't". McKinnon argues that such biologically centered constructions of relatedness result from a specific cultural context: the kinship category "mother" is relatively self-evident in Anglo-American cultures where biology is privileged but not in other societies where rank and marital status, not biology, determine who counts as a mother or where mother's sisters are also considered mothers and one's mother's brother is understood as the "male mother".^[54]

In a review of 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."^[55]

However, evolutionary psychologists point out that their research actually focuses on commonalities between people of different cultures to help to identify "human psychological nature" and cultural universals. 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.^[56]

Reductionism and determinism

Some critics view evolutionary psychology as influenced by genetic determinism and reductionism.^{[1][52][19][28][57][58]}

Evolutionary psychology is based on the theory that human physiology and psychology are influenced by genes. Evolutionary psychologists assume that genes contain instructions for building and operating an organism and that these instructions are passed from one generation to the next via genes.^[57]

Lickliter and Honeycutt (2003) have argued that evolutionary psychology is a predeterministic and preformationistic approach that assumes that physical and psychological traits are predetermined and programmed while virtually ignoring non-genetic factors involved in human development. Even when evolutionary psychologists acknowledge the influence of the environment, they reduce its role to that of an activator or trigger of the predetermined developmental instructions presumed to be encoded in a person's genes. Lickliter and Honeycutt have stated that the assumption of genetic determinism is most evident in the theory that learning and reasoning are governed by innate, domain-specific modules. Evolutionary psychologists assume that modules preexist individual development and lie dormant in the structure of the organism, awaiting activation by some (usually unspecified) experiential events. Lickliter and Honeycutt have opposed this view and suggested that it is the entire developmental system, including the specific features of the environment a person actually encounters and interacts with (and not the environments of distant ancestors) that brings about any modularity of cognitive function.^[57]

Critics argue that a reductionist analysis of the relationship between genes and behavior results in a flawed research program and a restricted interpretation of the evidence, creating problems for the creation of models attempting to explain behavior. Lewontin, Rose & Kamin instead advocate a dialectical interpretation of behavior 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 such as the hierarchical reductionism proposed by Richard Dawkins will cause the researcher to miss dialectical ones.^[59] Similarly, Hilary Rose criticizes evolutionary psychologists' explanations of child abuse as excessively reductionist. As an example she cites Martin Daly and Margot Wilson's theory that stepfathers are more abusive because they lack the nurturing instinct of natural parents and can increase their reproductive success in this way. According to Rose this does not explain why most stepfathers do not abuse their children and why some biological fathers do. She also argues that cultural pressures can override the genetic predisposition to nurture as in the case of sex-selective infanticide prevalent in some cultures where male offspring are favored over female offspring.^[60]

Evolutionary psychologists Workman and Reader reply that while reductionism may be a "dirty word" to some it is actually an important scientific principle. They argue it is at the root of discoveries such as the world being made up of atoms and complex life being the result of evolution. At the same time they emphasize that it is important to look at all "levels" of explanations, e.g. both psychologists looking at environmental causes of depression and neuroscientists looking the brain contribute to different aspects of our knowledge of depression. Workman and Reader also deny the accusation of genetic determinism, asserting that genes usually do not cause behaviors absolutely but predispose to certain behaviors that are affected by factors such as culture and an individual's life history.^[61]

Alternative explanations

Behaviors that reduce reproductive success

"Maladaptive" behaviors such as homosexuality and suicide seem to reduce reproductive success and pose a challenge for evolutionary psychology. Evolutionary psychologists have proposed explanations, such that there may be higher fertility rates for the female relatives of homosexual men, thus progressing a potential homosexual gene,^[71] or that they may be byproducts of adaptive behaviors that usually increase reproductive success. However, a review by Confer et al. states that they "remain at least somewhat inexplicable on the basis of current evolutionary psychological accounts".^[48] If seen to be of a maladaptive nature, and therefore disregarding the evolutionary psychological evidence for things such as homosexuality, these behaviours can simply be seen in a no different manner than other maladaptations such as poor eyesight.

Ethical implications

Many critics have argued that evolutionary psychology and sociobiology justify existing social hierarchies and reactionary policies.^[72][73] Evolutionary psychologists have 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 against social justice (e.g. the argument 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).^[59]

It has also been suggested by critics that evolutionary psychologists' theories and interpretations of empirical data rely heavily on ideological assumptions about race and gender.^[74] Halford Fairchild, for example, argues that J. Philippe Rushton's work on race and intelligence was influenced by preconceived notions about race and was "cloaked in the nomenclature, language and 'objectivity'" of evolutionary psychology, sociobiology and population genetics.^[75]

Moreover, evolutionary psychology has been criticized for its ethical implications. Richardon (2007) and Wilson et al. (2003) have cited the theories in A Natural History of Rape where rape is described as a form of mate choice that enhances male fitness as examples.^[73][11] Critics have expressed concern over the moral consequences of such evolutionary theories and some critics have understood them to justify rape.^[73][11] However, empirical research has found that, compared to a control group, exposure to evolutionary psychology theories had no observable impact on male judgments of men’s criminal sexual behavior.^[76]

Evolutionary psychologists caution against committing the naturalistic fallacy – the idea that "ought can be derived from is" and that "what is natural" is necessarily a moral good.^[73][77] In the book The Blank Slate, Steven Pinker contends that critics have committed two logical fallacies:

The naturalistic fallacy is the idea that what is found in nature is good. It was the basis for Social Darwinism, the belief that helping the poor and sick would get in the way of evolution, which depends on the survival of the fittest. Today, biologists denounce the Naturalistic Fallacy because they want to describe the natural world honestly, without people deriving morals about how we ought to behave -- as in: If birds and beasts engage in adultery, infanticide, cannibalism, it must be OK. The moralistic fallacy is that what is good is found in nature. It lies behind the bad science in nature-documentary voiceovers: lions are mercy-killers of the weak and sick, mice feel no pain when cats eat them, dung beetles recycle dung to benefit the ecosystem and so on. It also lies behind the romantic belief that humans cannot harbor desires to kill, rape, lie, or steal because that would be too depressing or reactionary.^[78]

Similarly, the authors of A Natural History of Rape, Thornhill and Palmer, as well as McKibbin et al. respond to allegations that evolutionary psychologists legitimizes rape by arguing that their critics' reasoning is a naturalistic fallacy in the same way it would be a fallacy to accuse the scientists doing research on the causes of cancer of justifying cancer. Instead, they argue that understanding the causes of rape may help create preventive measures.^[73][79]

Wilson et al. (2003) have stated that evolutionary psychologists are themselves confused about the naturalistic fallacy and misuse it to forestall legitimate ethical discussions. The authors have argued that a factual statement must be combined with an ethical statement to derive an ethical conclusion. Thus, "ought" cannot be described exclusively from "is". They have suggested that if one combines Thornhill and Palmer's theory that rape increases the fitness of a woman's offspring with the ethical premise that it is right to increase fitness of offspring, the resulting deductively valid conclusion is that rape has also positive effects and that its ethical status is ambiguous. Wilson et al. have stated: "Any critic who objects to Thornhill and Palmer's evolutionary interpretation of rape on ethical grounds is dismissed with the phrase 'naturalistic fallacy' like a child stupid enough to write 2+2=5, stifling any meaningful discussion of the ethical issues surrounding the subject of rape. Yet, it is Thornhill and Palmer who are thinking fallaciously by using the naturalistic fallacy in this way." However, in the same article these authors also note that "...we want to stress that we are sympathetic with the goals of evolutionary psychology and think that research should proceed on all fronts, including the possibility that unethical behaviors such as rape evolved by natural selection".^[73]

Political stance

Part of the controversy has consisted in each side accusing the other of holding or supporting extreme political viewpoints: evolutionary psychology has often been accused of supporting right-wing politics, whereas critics have been accused of being motivated by Marxist view points.^[35][80]

Linguist and activist Noam Chomsky has said that evolutionary psychologists often ignore evidence that might harm the political status quo:

The founder of what is now called "sociobiology" or "evolutionary psychology"-the natural historian and anarchist Peter Kropotkin-concluded from his investigations of animals and human life and society that "mutual aid" was a primary factor in evolution, which tended naturally toward communist anarchism....Of course, Kropotkin is not considered the founding figure of the field and is usually dismissed if mentioned at all, because his quasi-Darwinian speculations led to unwanted conclusions.^[81]

Chomsky has also said that not enough is known about human nature to point to any political conclusions.^[81]

Evolutionary psychologist Glenn Wilson argues that "promoting recognition of the true power and role of instincts is not the same as advocating the total abandonment of social restraint".^[82] Left-wing philosopher Peter Singer in his book A Darwinian Left has argued that the view of human nature provided by evolution is compatible with and should be incorporated into the ideological framework of the Left.

Evolutionary psychology critics have argued that researchers use their research to promote a right-wing agenda. Evolutionary psychologists conducted a 2007 study investigating the views of a sample of 168 United States PhD psychology students. The authors concluded that those who self-identified as adaptationists were much less conservative than the general population average. They also found no differences compared to non-adaptationist students and found non-adaptationists to express a preference for less strict and quantitative scientific methodology than adaptationists.^[83]

See also

• Biopsychiatry controversy

References

Further reading