Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature

The field formerly known as Sociobiology has reinvented itself under the name Evolutionary Psychology, though with more of a focus on internal psychological mechanisms. The premise remains the same: current human behaviors or tendencies can be explained as adaptive mechanisms implanted in us by our evolutionary past. The field has gained tremendous attention in the popular media; you can hardly read an issue of Science Times without seeing an example of it. We are barraged with new hypotheses, such as the claim that our preference for green lawns is due to the fact that we evolved on the African savanna (perhaps our love of TiVo is because it allows us to hunt wildebeests during prime time?). But as David Buller demonstrates in his brilliant book, the emperor still has no clothes. Though Buller is a philosopher, he presents an internal critique of the field, that is a demonstration that EvoPsych is wrong on biological and evolutionary grounds. Buller is especially strong in his critique of the assumption of the "modularity" of mind (that the mind is a collection of separate modules for different function), a virtual article of faith in EvoPsych. This book is simply a must-read for those interested in this topic or in evolution and human nature. For some reason, some people feel threatened by the fact that it is a philosopher rather than a biologist criticizing EvoPsych. But this is an example of the ad hominem logical fallacy; the question is not what academic department Buller belongs to, but whether his arguments are valid. Whatever your opinions on EvoPsych, you cannot ignore this extremely important book.

Unlike reviewers of mystery novels, commentators on this book need not hesitate to reveal the ending. The author thinks evolution teaches us 'human nature' is a superstition, and that generalizations in human psychology do not attain the status of "laws of nature". In fact, pace those who consider themselves familiar with "duck nature," Buller thinks that there are NO biological species that have the logical status we ordinarily accord to those mathematical (or physical, or chemical) kinds which can be understood as classes each of whose members are definitionally required to exhibit a set of separately necessary and jointly sufficient properties. Ducks are not typed in the way that equilateral triangles are typed. This will not surprise a careful reader of the magisterial work of the late great zoologist Ernst Mayr, who repeatedly reminded us that species are polymorphic, related not by class membership but by lineage or descent. To put it more simply and from a different perspective, a fundamental requirement of Darwin's theory is the occurrence of significant individual variability within species. We know that not all natural selection is "canalizing selection" funnelling all variation toward an optimal type. "Frequency dependent" selection is alive and well, and the world is full of hawks and doves, to say nothing of the bourgeoisie. To put it colloquially, not all of us search "for a girl just like the girl that married dear old dad." When my old dog had pups, some of them were good hunters, some were suitable for nothing but footstool warmers; when raising hens, farmers' wives cook the poor layers for dinner. It is important to emphasize that Buller seeks to defend evolutionary psychology by criticizing the excesses of Evolutionary Psychology, rightly considered as a the product of a collective, or tribe, of investigators (Cosmides & Tooby, David Buss, Steven Pinker) and journalists (Nicholas Wade, Robert Wright, Matt Ridley) sharing a common set of presumptions about evolution (adaptationist), about cognitive science (massive modularity), and about the nature of culture (reducible to individual psychology). Robin Dunbar makes a similar point in noting the guerilla warfare waged by proponents of Evolutionary Psychology against dissidents who might be considered behavioral ecologists, because they don't subscribe 100% to the major tenets of Evo Psycho: e.g., because they study the contributions made by behaviors currently observable to the biological fitness of organisms currently alive. It won't do to label Buller a philosopher and not a working scientist. Perhaps philosophers are a dying breed, but they have time to read a great many books, and erudition matters when the issue is the comparative evaluation of diverse and competing scientific research programs. Historians and philosophers of science are like the prairie dogs who understand that sometime it's a good idea to quit eating and survey the neighborhood. O

This book makes a strong case that there are problems with claims put forth by leading Evolutionary Psychologists, but the problems are somewhat less important than the book tries to imply. This is the most serious and careful attack on Evolutionary Psychologists so far. But it is often hard to tell to what extent the theoretical claims he attacks are reflect bad theories or whether some of them are just careless misstatements by people who are too focused on attacking the tabula rasa worldview to worry about criticisms from other viewpoints. For instance, it's hard to believe that the Evolutionary Psychologists mean the word "universal" in the phrase universal human nature as literally as Buller takes it. He presents strong arguments that Evolutionary Psychologists have overstated the extent to which dna encodes specialized mental modules, and presents detailed arguments that their empirical results have been sloppy and at least slightly biased against the idea of a general-purpose mind. But if Evolutionary Psychologists are willing to modify their theory to refer to somewhat less specialized modules whose features are influenced by dna in less direct and more subtle ways, then the features of their theories that they seem to consider most important will survive. His analogy with the immune system illustrates how a system that looks at first glance like it requires some fairly detailed genetic blueprints can actually be caused by a general purpose system that learns most of its specializations by reacting to the environment. This is not in any way an attack on the idea of using evolutionary theory to understand the mind. In fact, he even points out that Evolutionary Psychologists have been overly interested in questions asked by creationists rather than those that evolutionary theory suggests are important. Ironically for a philosophy professor, his weakest arguments are the most philosophical ones. He correctly points out the problems with using an essentialist notion of species that is based on universal phenotypic characteristics, but then proposes a definition of species based on continuity and spatiotemporal localization that seems as essentialist and as far from what people actually mean by the word as the definition he criticizes. If I understand his definition correctly, it implies that recreating a Dodo from dna would produce a new species. He should study the philosophy of concepts a bit more (e.g. Lakoff or the neural net literature) and decide that the concept of species doesn't need either type of essence, but can instead be a more probabilistic combination of several kinds of attributes.

An excellent book in which David Buller (a philosopher of biology at NIU) considers in detail some of the strongest claims made by Evolutionary Psychologists (the likes of Pinker, Tooby, Cosmides, etc.) for a "universal human nature" arising from psychological adaptations of the human mind during the Pleistocene. Beware that the writing is dense and you will need to concentrate to follow all the arguments; the book is long and not an easy read. As a scientist I have always been skeptical of the second part of the saying, "philosophy without science is empty, science without philosophy is blind" (of which Buller's web page reminded me), but Buller's book gives a very convincing example of science (a specific type of "Evolutionary Psychology") which, in its eagerness to explain human nature, seems to have taken some dangerous "leaps of faith". Buller's book could be easily dismissed as a simple criticism of Evolutionary Psychology, but the detailed test of some well publicized ideas is only part of the work. Buller starts with an engaging four-chapter introduction, considering in detail the concepts of evolution (1), mind (2), adaptation (3), and modularity (4). These, together with the last chapter on "human nature", contain the basis of his understanding of evolution and its implications for the evolution of human behavior. The remaining three chapters consider in excruciating detail the specific arguments for and against some of the central tenets of Evolutionary Psychology -- on human mating preferences, marriage, and parenthood. Buller argues that evolution is a process, not a framework which uses natural selection to explain finished products. He argues that Homo Sapiens and all species are "individuals" (spaciotemporally localized, continuous and cohesive) in view of evolution and not "natural kinds" (defined by an essential characteristic), that human psychological mechanisms are homologies (unified by common descent) and will not follow simple laws of nature that pertain exclusively to the human mind (although they will follow laws that pertain to all evolved minds). He suggests that the human universals that we observe today are not necessarily evidence of physiological universals evolved as adaptations when humans were hunter-gatherers. Some observed "cultural universals" could be a result of frequency-dependent selection within populations that has succeeded in maintaining similar balanced polymorphisms of psychological phenotypes in most cultures. He cites epidemiological culture as another possibility. This is easily the most thought provoking book I have read on "human nature" for a variety of reasons. First, Buller never simply criticizes other people's ideas by criticizing their proponents and/or changing the subject and criticizing other aspects of their work. He is content to criticize the ideas themselves based on their contextual frame and existing empirical support. Moreover he is always careful to define precisely the asp

Buller's fair-minded and generally gentle critique of evolutionary psychology is well considered and strong. One almost wishes, however, that he had not occasionally chosen to thumb his nose at EvPsych orthodoxy, for example by choosing a title so close to that of Tooley and Cosmides' own 1992 polemic "Adapted Minds". Buller's grasp of evolutionary theory is strong, and his application of it responsible -- he cogently pinpoints the faults of previous critiques of evolutionary psychology, for example that of Leontin and Gould. He also applies a philosopher's grasp of logic to the notoriously problematic Wason task that unfortunately lies at the heart of the EvPsych "social exchange" theory. Problems with the Wason task, both within and between studies, are rampant, and hardly limited to its use by Cosmides and her collaborators; but this does not mean that Buller is in any way wrong to point out that the use of the task in key EvPsych studies displays problems both of experimental design and interpretation of results. Handwaving about how cheater detection and deontic logic are coextensive mental capacities aside (ironic because Cosmides herself has published papers claiming the opposite), one needs only the appreciation of translation difficulties granted by an elementary course in formal logic to realize that claims about "switched" sentence structures giving "switched" logical forms, independent of context, are extremely questionable; claims about the representative ability of logic that restrict themselves to the propositional calculus (ignoring even first-order logic, much less modal logic) are embarassing. What is more noteworthy is that despite claims about mate selection and child abuse based essentially on the mining of public data of questionable reliability, the cheater-detection result is one of the only EvPsych results claiming to demonstrate a domain-specific improvement in performance over general reasoning processes on a concrete, repeatable cognitive task. We should certainly be excited about the potential of evolutionary psychology to deliver genuine explanations about the nature of human cognition, particularly in the social domain, where diverse results from other areas of work (e.g. motivated reasoning research) make it clear that there is _something_ beyond simple logical processing going on. But it is unfair to take Buller to task simply because he -- correctly, in my opinion -- points out that, thus far, the enthusiastic and broad theories of evolutionary psychology are a check that the basic experimental results cannot cash. After 20 years of work, it is fair to ask whether evolutionary psychology has in fact earned the great excitement generated by the bold theoretical pronouncements and initial experimental successes of its early days. This is an important book because it casts a critical, but not rancorous, eye over the playing field and asks where, thus far, the pieces have landed. As another reviewer sugges