On trial again: sociobiology et al.

Sense and Nonsense: Evolutionary Perspectives on Human Behaviourby Kevin Laland and Gillian Brown Oxford University Press, 2002. US$29.95 hbk (150 pages) ISBN 0 19 850884 0The title of this book suggests that we will learn what is wheat and what is chaff in evolutionary studies of human behavior. The book is organized as though this were its goal, with a core section of five chapters, each leading to a ‘critical evaluation’ of a different evolutionary discipline (sociobiology, behavioural ecology, evolutionary psychology, memetics and gene-cultural evolutionary biology). In the course of being critical, Laland and Brown (LB that is, they accept untested speculations about the adaptive significance of our behavior. Moreover, LB 80: 530–533See all References[2] and mimicked by almost every sociobiological opponent since then, notwithstanding the many published rebuttals. If, however, sociobiology truly promoted the acceptance of untested speculations (fables) about the adaptive basis of behavior, surely the discipline would have failed. But it is alive and well because sociobiologists and their ilk use the hypothetico-deductive method in the same way as other scientists. If L&B were going to repeat the just-so story charge again, they had an obligation to name names and identify purely speculative research papers. This they do not do.L&B also prefer to describe, rather than firmly evaluate, the bickering that has gone on between anthropologists working on human behavioral ecology and psychologists who study the evolution of psychological mechanisms. Some in the anthropological camp believe that one can test evolutionary hypotheses about the adaptive value of behavioral traits by studying the behavior and reproductive success of people living in traditional societies. However, some evolutionary psychologists believe that, by contrast, the focus must be on the adaptive features of the universal psychological attributes of humankind. The book summarizes the arguments clearly. But, despite describing some examples of thoroughly successful research by human behavioral ecologists, the authors never reach the logical conclusion that evolutionary psychologists have got this one wrong.In addition, although L&B do note the connection between human behavioral ecology, evolutionary psychology and sociobiology, they generally treat the three fields as separate entities. Nowhere do they say that the three ‘disciplines’ are not just similar, they are identical in all the important particulars. All three are based on the assumption that natural selection has affected the evolution of our behavior. All three use selectionist theory to develop adaptationist hypotheses, which they then attempt to test. L&B could have told us that the differences among the subdisciplines are essentially superficial, arising primarily from academic tribalism (psychology versus anthropology versus biology) and the tendency of researchers to overstate the novelty of their own contributions.In this regard, the authors could have made a much stronger case that memetics is not as earth-shaking as some proponents have claimed. Memeticists have applied natural selection theory to the transmission of competing ideas and traditions through human cultures. For these researchers, the meme is the unit of selection and the human brain is the environment in which memetic competition occurs. The puzzle at the heart of memetics is: why do some ideas spread from person to person (brain to brain) despite their neutral or negative effects on individual fitness? The phenomenon of maladaptive phenotypes has long attracted the attention of evolutionary biologists. Indeed, the authors themselves explain how fitness-damaging behaviors can arise as dysfunctional by-products of evolved mechanisms that generally promote reproductive success. (A classic example is the evolved fondness for sugars and fats, which enhances fitness in environments in which these foods are scarce, but which can lead to obesity, illness and premature death in modern environments oversupplied with sugars and fats.) Memetics is one small twig on this branch of existing evolutionary theory, and should be identified as such.Therefore, although I can recommend Sense and Nonsense for its complete coverage of the arguments for and against the evolutionary study of human behavior, I wished for a bit more bite in the evaluation of those arguments.