Henry Plotkin’s Evolution in Mind is the sensible face of evolutionary psychology. While sanguine about the promise of evolutionary psychology he avoids much of the eulogizing tone that characterize other introductory texts. His account is strong on the history of psychology, on tracing the emergence of evolutionary psychology, and his examples of the current work of evolutionary psychologists is largely limited to ones that have a strong and prolonged set of results to support them.

The main argument in favor of an evolutionary psychology offered by Plotkin as well as others is that there is little doubt that the human body has evolved and since there is little doubt about this, then it seems plausible that the human mind has evolved as well. Viewed in such a way evolutionary psychology encompasses a broad range of enterprises. However, evolutionary psychology is increasingly becoming associated with a particular school of thought rather than with this general study. And the former is where Plotkin’s book is located. This school of thought holds that the human mind is a computer (or information-processing device) that is made up of specialized mechanisms which are adaptations to problems of reproduction and/or survival faced by our hunter-gatherer ancestors.

As one would expect from a book on evolutionary psychology there is an account of key ingredients of evolutionary theory. Plotkin not only introduces Darwin’s theory of evolution by natural section but also Hamilton’s Rule and an account of the replicator/interactor distinction. Chapter 1 asks ‘Just What Kind of Science is Psychology?’, Plotkin’s answer is that it is an evolutionary one. In Chapter 2 Plotkin addresses the nature/nurture problem. He explicitly rejects that nature and nurture are separable causes of behavior, instead of such a dichotomy, behavior is argued to be always and everywhere the interaction of both nature and nurture. However, Plotkin’s ‘resolution’ of the nature/nurture problem turns out to be a familiar attempt to reduce nurture to nature, he asserts "…nature has itself evolved…" (p. 37).

Chapter 3 considers what Plotkin calls ‘The Revolution in Our Neighbor’s House’, the emergence of Sociobiology. Sociobiology can be seen as the attempt to explain social behavior in term of evolutionary biology. The crucial sociobiological question is ‘How does this behavior allow the organism to pass on its genes?’ Plotkin outlines the limitations of much of sociobiological work, noting that while sociobiological claims are plausible that is all they are because in every case there are alternative explanations. He goes on to argue that ‘culture’ presents a serious problem in the application of sociobiological theory to humans. Unlike other organisms culture allows humans to transmit ‘extra-genetically’ large quantities of complex information to each other. Plotkin attempts to address the question of how culture and genes are related in Chapter 6.

In Chapter 4 Plotkin discusses the most important theoretical claim of evolutionary psychology, namely, that the human mind is made up of a large number of specialized mechanisms. And in Chapter 5 two examples of such purported mechanisms are outlined: a theory of mind mechanism and causality mechanism. The former is the claim that the mind contains a mechanism that allows inferences about the beliefs and desires of others (this is not, however, a ‘mind-reading’ mechanism). The latter is a specialized mechanism that primes or predisposes human to learn certain features of the causal structure of the world.

Two key arguments are presented in support of the claim that the human mind is made up of a large numbers of specialized mechanisms: the first is that the mind has to be built out of specialized parts because it has to solve specialized problems while the second holds that specialized mechanisms are quicker, more reliable, and are more efficient than more general ones. However, both these arguments face serious problems. For example, the first argument appears simply mistaken. The human hand is a single trait but it can perform many specialized tasks: it can be configured into a hook grip (to lift a pail), a scissors grip (to hold a cigarette), a three-jaw chuck (to hold a pencil), etc.. While the mind may indeed contain some specialized mechanisms such as the theory of mind mechanism there is a danger of conflating the specialized nature of an outcome with the specialization of the mechanisms used to achieve that outcome. Thus, while we may have the specialized ability to play chess this kind of thinking did not evolve for the purpose of playing chess. So there must be some degree of generality to the problem-solving thought that goes into chess. Plotkin appears to be aware of this danger but the evidence he presents does not avoid it.

As mentioned above Plotkin attempts to address the question of how culture and genes are related in Chapter 6. However, just as in Chapter 2 he attempts to reduce nurture to nature he attempts to do the same with culture. The thought here is that "…culture is part of our biology…" (p., 111). However, the problem with such reductionism is that many if not all cultural phenomena don’t seem to be able to be explained in terms of biology. For example, there are no known biological laws that explain the rise of Seattle Grunge or the fall of Disco. Evolutionary psychology, the general study, has much to offer, however, the school of thought faces some trying problems. However, if you want an account of the latter from the horse’s mouth, so to speak, the most sensible one is Plotkin’s.

Terence Sullivan is a Ph.D. student in philosophy at the University of Utah where he is a Steffensen-Cannon Scholar. His dissertation topic is provisionally entitled The Wrongs and Rights of Evolutionary Psychology. More generally his research interests are the philosophies of biology and mind, epistemology, metaphysics, and Marxism.

Categories: Genetics, General