Recently—after a long night of drinking—I was embarrassed to find myself sputtering at a good friend with anger over a primarily academic issue. She and I disagreed over this question: Do most women feel that their social standing depends upon appealing sexually to men, in exchange for money and favors?Upon recently reading a seminal work by biologist E.O. Wilson, my friend was (much to her own chagrin) convinced for the first time that men and women inhabit generally fixed and mutually exploitative gender roles. What’s more, she now saw this arrangement as a biologically determined fact of life. Trained in neuroscience, I found hers to be a deeply troubling perspective.

E.O. Wilson argues that human nature is a biologically fixed pattern. Wilson is in the good company of a number of other respected scientific luminaries; some of my favorite thinkers (mostly Steven Pinker, and to some degree Richard Dawkins) have shown themselves at least sympathetic to, if not active contributors to the same field of study. But in stumbling across the field of sociobiology—and its intellectual twin, evolutionary psychology—I find flaws in how both fields purport to connect modern behaviors with explanations that appeal to the conditions of natural selection.Sociobiology proceeds from within the fields of evolutionary biology and genetics, while evolutionary psychology stems from, and uses the research techniques of, psychology and neuroscience. Both risk becoming a horrifying inversion of their original disciplines' project and intent. Evolutionary psychologists will often claim that their studies are fundamentally no different from evolutionary investigations of physiology. But in order to study something from an evolutionary perspective, we need to assume that it is modular, discrete and has a predominately biological basis. Therefore, lucid explanations regarding behavior are much more elusive than those regarding physiology.

While behavioral functions may be in some way modular (though this is contentious, and we have not yet conclusively demonstrated the specific pathways and mechanisms for any complex behavior), they are most certainly not discrete in the sense of operating independently from other processes. Most importantly, given a total paucity of evidence, we cannot conclude that any specifically human behaviors are based primarily in biology. This foregoes ascribing behaviors to adaptive features of that biology.One problem arises from the nature of cultural transmission: We have limited ability to suss out which behaviors are generated by biological processes, versus which are passed down or learned culturally.  Evolution scientists take cross-cultural, Jungian characteristics of complex human behavior (such as gender roles, sexual jealousy and religious belief) as evidence of the biological nature of behavior. But these phenomena are contingent on broader culture within a society, and could have radically different functions from what is supposed by later or external observers.

In order to establish the presence of cultural universals (which must necessarily exist, if we are to draw conclusions about behavior that apply to all humans), we must assume that the array of cultures we see today represents a reasonable proxy of all possible cultures. While not directly inside my specific area of study, lingustics offers an analogy for this problem in evolutionary psychology. Appeals to cultural universals often invoke linguistic explanations, as scholars have identified certain features that appear in all human languages. What would come of evolutionary psychology if the late 19th century linguistic hypothesis of a Nostratic (read: “common”) Eurasian ur-tongue were to be suddenly proven? Since commonality of language implies commonality of culture, finding that the vast majority of modern human cultures descend from a common mother would indicate that the human behaviors that we see are only a tiny subset of all possibilities for human expression.

That is to say, it would render the notion that there are behavioral universals even more preposterous, since there exist an infinite array of possibilities for culture-directed behavior that we will never see.Assigning behaviors a primarily genetic or physiological explanation, while hopping straight over the issues of culture and cultural transmissions, is quite simply that: jumping to conclusions. In failing to account for the infinite possibilities of culture and environment, making arguments about what is genetically programmed into our behavioral palette is not a scientific endeavor. It is fun to speculate, but speculation is the furthest thing imaginable from science.

The “state of nature” that evolutionary psychologists frequently refer to—i.e., the social and geographic structure of proto-human life that exerted the evolutionary pressure to produce our present-day genetics and biology—is similarly baseless. In fact, this concept best represents the deeply circular nature of evolutionary psychology logic. In order to concoct a story of what would have represented adaptive behaviors in the human environment, a reconstruction of those conditions must be drawn. Since we lack, however, anything but the flimsiest extrapolations of extremely limited archaeological data, these reconstructions must be inferred from our present-day genes and behavior. One cannot coherently link past to present with no vouchsafe knowledge of the past.An example of this insufficiency comes from a common argument advanced by evolutionary psychologists Martin Daly and Margo Wilson, to explain the violence that men often display towards children in the form of the stepfather module. In this hypothesis, men possess a mental function that makes them likely to kill their stepchildren. Daly and Martin implicitly construct a vision of the ancestral past in which men 1) commonly adopted stepchildren, 2) saw said children as too costly and so 3) killed them.

This entire chain is unverifiable, as we can only speculate on these prehistoric behaviors. Without proven historical antecedent, we have only a culturally, temporally specific behavioral pattern—and little proof that such behavior has roots in common human evolution. How do scientists suss out whether what drives male violence towards stepchildren is cultural, biological or entirely incidental—as some newer research, which suggests that a much higher proportion of stepfathers were prone to violence in general before becoming stepfathers, would indicate? The same newer research also indicates that violent stepfathers are equally as likely to be violent towards their own children—something that makes no sense in the cost-benefit analysis of this proposed evolutionary psychological module (Temrin, Nordlund, Rying, and Tullberg).

Even if the practices of evolutionary psychology were scientifically sound—which they most certainly are not—the field is a project in social irresponsibility. In practice, evolutionary psychology sells a moral justification to the public of present-day power structures and political hierarchies. Modern and recent historical social structures imply genes that render males physically, sexually and socially dominant. In my view, this is why evolutionary psychologists presume that the first human males were out hunting, while the women gathered foodstuffs close to home.

In the book A Natural History of Rape: Biological Bases of Sexual Coercion, biologist Randy Thornhill and his collaborator, anthropologist Craig Palmer, advance the argument that forcible sexual intercourse, as instigated by men on women, is likely an evolved and adaptive trait. The presumption made by the authors, and acknowledged in the work, is that rape must be a reproductive strategy: Men select their victims on the basis of perceived fertility, in order to maximize the number of children they would produce. The authors don't control for modern drug-aided rapes, incest rape or same-sex rape.Putting aside the issue neuroscience has with most EP studies—being that we have no evidence to suggest that there is a fixed, common mental module that corresponds to the observed activity of “rape”—this work makes the enormous scientific misstep of assuming that the rapist’s behavior is a sound reproductive strategy. This is a monumental assumption. The authors do not bother to prove that rapists have more children. More importantly, they do not prove that prehistoric rapists had more children. It is not at all apparent that rape is or was a successful reproductive strategy, especially when considered in a social context: Rapists are generally imprisoned, if not killed for their behavior, and babies produced by rape are often neglected, or even euthanized.Given evolutionary psychology’s fixation on sex, its proponents often characterize it as a radical or transgressive discipline. Nothing could be further from the truth. Such proponents should know better. In line with the just-world hypothesis, people are already inclined to believe that powerful people are that way due to some sort of innate property. When evolutionary psychology addresses apparently pathological behavior, it does so under the premise that there is in fact an “evolutionary” or adaptive reason for that behavior. This renders such behavior, in effect, untreatable. This is a position with political implications.

The brain is a fiendishly complex instrument, and it is also far from a perfectly constructed one. There is not necessarily any reason to believe that all, or even most of our behaviors have an explicit and efficient evolutionary basis. I am categorically a monist and a materialist. The notion that our behavior is entirely determinate, as a function of biology and culture, strikes me as more than plausible. However, the precise ways in which this is true, and the distinction between origins biological and cultural, are far beyond our means to affirm as scientists today. The void presented here by rigorous science has inevitably been taken up by the moral and aesthetic preferences of the powerful within our epoch. At least one good thing that can be said for the popular science audience right now: We've mostly given up on the “objective” studies of racial inequality so popular with the intellectual predecessors of sociobiologists in the 19th and early 20th centuries.Nonetheless, at the moment, we seem to be a largely misogynistic, fundamentally materially acquisitive society. Thus, the findings of sociobiologists and evolutionary psychologists support this cultural paradigm under the guise of science. Such figures are rewarded with book sales, academic appointments and public prominence because they serve the general function of the media: telling powerful people that their position is natural and justified. Behavior that is considered selective or maladaptive is premised on the moral preferences of the author, and her or his audience.

There are a number of proponents or practitioners of evolutionary psychology for whom I have a great deal of respect. Many have made tremendous contributions to neuroscience and cognitive psychology. But to me, the field of evolutionary psychology more commonly brings about certain fallacies where science can historically go horrifically wrong. Evolutionary psychology raises only narrative possibilities–explanations and mechanisms that could conceivably account for a behavior. It does not, however, employ objective techniques to arrive at either theory or proof.

By contrast, neuroscientists must employ scientifically rigorous techniques of dissociation before making declarations about what does or does not constitute physiologically determined behavior. By determining that a lesion to one particular structure in the brain affects one very specific external behavior, neuroscientists can isolate a behavior’s physiological root (Van Orden, Penington and Stone, 2001). Neuroscience also informs us that the brain is an imperfectly constructed instrument that can easily produce aberrant behaviors devoid of any efficient evolutionary basis. Evolutionary psychology, by contrast, rarely if ever makes reference to dissociation studies in order to discern whether or not a behavior has a specific physiological root. Without this evidence, applying the label “evolutionary” is not scientifically justified.