In the concluding pages of this book, Richerson and Boyd observe that universities have introductory courses in psychology, sociology, economics and political science in which students "are encouraged to think that the study of humans can be divided into isolated chunks corresponding to these historical fields." There is, however, no Homo Sapiens 1 or 101, "a complete introduction to the whole problem of understanding human behavior." The authors note that the chief reason no such course exists is "that the key integrative fields have not yet developed in the social sciences" and that "a proper evolutionary theory of culture should make a major contribution to the unification of the social sciences. Not only does it allow a smooth integration of the human sciences with the rest of biology, it also provides a framework for linking the human sciences to one another." I believe that such an evolutionary theory can and should integrate the social sciences with each other and biology and that this book could and should serve as the foundational text for Homo Sapiens 101.
There are dozens of books available employing evolutionary thinking to humans, the large majority of which do not offer a "proper evolutionary theory" because they neglect the most obvious and unique feature of our species--our culture, information affecting behavior acquired from other humans through social transmission. This failure results from a steadfast dedication to accounting for human behavior in terms of principles applicable to the prosocial behavior of other species-- kin selection and reciprocity. In an attempt to not stray from "orthodox" neo-Darwinism, neo-Darwinians have failed to fully acknowledge, let alone explain, the most salient feature of our species--a fact that "social contructivists" use to dismiss evolutionary theory. Richerson and Boyd recognize the "ancient social instincts" of kin altruism and reciprocity but they also acknowledge and give appropriate attention to what they call the "tribal social instincts." These instincts, which probably emerged during the dramatic climate variations of the late Pleistocene, allow members of our species to identify with, dedicate themselves to, and take normative direction from, groups of people that include hundreds to thousands of people beyond kin and friends. These tribal instincts are accommodated in complex societies such as our own through "work-arounds," institutions such as religious organizations, political parties, voluntary associations and other symbolically marked groups that exploit our inclination toward particularistic community attachment. Originally, though, these instincts coevolved in a ratcheting process with our language, capacity for perspective taking, morality, religion and "culture" broadly conceived. We are a thoroughly unique groupish species and the only species on which group selection of cultural variants has played a role. As Richerson and Boyd argue, genes and culture have coevolved within our species. Culture has been primary in the environment selecting features of our genotype. Those humans incapable of cooperating in tribal settings were ostracized and were unlikely to find mates. They were less likely than cooperators to survive and reproduce. Culture has molded our genetic make-up just as our genes have directed the development of our culture.
I do not have space here to outline Richerson and Boyd's theory of cultural evolution beyond noting that population thinking plays as prominent a role as it did in Darwin's thought. I can say that unlike their landmark book, Culture and the Evolutionary Process (1985), this book is accessible to any adult with a three digit IQ. I can also note that the authors are both modest and civil toward those with whom they disagree--characteristics that portray their training in the natural sciences instead of the social sciences. They are quick to acknowledge when empirical evidence is currently lacking to substantiate claims they are making, and they are always generous to their intellectual opponents. For example, they acknowledge Richard Dawkins' contributions to evolutionary theory, while demonstrating the deficiencies of his "meme" theory of culture; they faithfully reproduce the arguments of evolutionary psychologists concerning domain-specific mental modules, while showing the dangers of overly-adaptationist accounts of our mental mechanisms; and in their discussions of various religious groups--Mormons, Catholics, the Amish, Hutterites, and the earliest Christians--Richerson and Boyd are deeply respectful of religious believers, something utterly missing in the writings of non-believers such as Richard Dawkins. This respectful attitude issues not from an impulse to pander but, rather, from an appreciation for our species-wide groupish tendencies and the accomplishments of symbolically marked groups, religious and otherwise.
Perhaps the largest contribution this book will make if it attains the number of readers it deserves is that it provides Darwinians and social constuctivists in the social sciences and the humanities grounds for common discussion and possible agreement. This is no small feat given the tendency of these symbolically marked groups to deem their in-group members angelic and those in the out-group moronic, if not demonic.
Brad Lowell Stone