Not by Genes Alone: How Culture Transformed Human Evolution [Paperback]

This is a remarkably comprehensive guide to recent research into the interaction between human culture and biology. The academic authors, an environmental scientist and anthropologist respectively who call themselves for the purpose of the book `environmental theorists', have integrated the research of many others with theories of their own. One of the strongest points of the book is its promotion of recent discoveries about the extraordinary climatic conditions that shaped humanity, literally earth-shaking information that makes new sense of human evolution but is often not taken into sufficient account. I assume that the inspiring, almost lyrical, treatment of this new information comes from the environmental scientist.

Overall, this is not a popular science book, though it is more readable than most scholarly texts. What stops it being popular science is perhaps the lack of an easy-to-grasp narrative with a beginning, a middle, and an end. The more comprehensive the research gathered the harder this gap is to fill, and it is to their credit that the authors have managed to link together such wide-ranging research from so many disciplines even if the linking theory seems sometimes contradictory, unclear, and over-complex with its many types of cultural transmission "biases" which account for everything. At times they seem to be hinting that culture is a sort of test-bed for natural selection, and that software will eventually be turned into silicon, so to speak. This would be the ultimate `gene-culture coevolution'. What else can they mean in the book's conclusion (p. 235) by: "In the short run, cultural evolution, partly driven by ancient [i.e. pre-human primate] and tribal social instincts and partly by selection among culturally variable groups, gave rise to the institutions we observe. In the longer run, cultural evolutionary processes created an environment that led to the evolution of uniquely human social instincts." Even if they are not propounding a theory that natural selection is using culture to beta test its new releases, they certainly seem to link nature and nurture more closely than other authors. On the same page they say "Without the ancient social instincts, we can't explain the many features of our social systems that we share with other primates". But we can. There are other ways to explain how dominance and bullying could arise in human societies a million years after it had vanished from the ancestral genome. This is the distinction between `homologous' and `analogous' evolution which the behavioural ecologists have emphasised.

The authors sometimes rely on a view of genetic evolution which was showing its age even at the time of publication. They claim to find cultural analogues of group selection, for example, which nowadays does not always mean one group out-competing another group. On page 208 they assemble the evidence that foragers frequently indulged in group combat, in support of Darwin's view that it led to the evolution of the social instincts, but admit that the data refers to either horticulturists or to foragers who were being forced into a small and smaller space by colonists.

The authors hold that `thinking about culture using Darwinian tools opens many new avenues for investigation.' One of these avenues that the authors have followed is `cultural maladaptation' analogous to what Richard Dawkins calls `misfirings' or `Darwinian mistakes'. The main human cultural maladaptation, in Richerson and Boyd's book, is the demographic transition: the reduction in fertility in developed countries. "Modern low fertility does not maximise fitness" (p. 173), and "The evolutionary potential of culture makes possible ... spectacular maladaptations, such as the collapse of fertility" (p. 115). At first one wonders if they are taking a position on the world population question, but it is more likely that they are disappointed that a simple model of more successful parents passing on both their genes and their high culture as a single package - allowing pure `coevolution' - is not applicable. Some would say, taking a more modern view of natural selection, that the differential reduction in fertility may not be a maladaptation at all; the eusocial insects manage to limit reproduction to certain castes and the ants alone now constitute a biomass equal to humans. Until recently it was thought that this behaviour could only evolve in closely-related populations, but recent research has shown that relatedness may not be the driving force behind eusociality. It is well within the bounds of possibility that humans have invented a culture which maximises fitness by allotting the tasks of having children and teaching them to different castes: a division of labour if you will admire the pun.

In the final analysis, what makes this book great is that the authors have assembled a remarkable collection of research and have gone to the trouble of interpreting it and taking positions. These positions will engage the attention of the thoughtful reader who can question them on the basis of the evidence presented. Whatever new theory and research in gene-culture coevolution captures our imagination in years to come, it will have been inspired by this book.

Some years ago, Richard Dawkins published "The Selfish Gene", explaining how gene survival was fundamental in natural selection. He also coined the term "meme" to explain the dissemination of ideas across societies. Almost immediately, there was a strident chorus of objection, based on the theme of "you can't say that about humans!" The outcry hasn't ceased, but in the case of Richerson and Boyd, it's become somewhat muted. This book is designed to gently persuade you that human evolution rests on a solid "cultural" base. Biology is under there somewhere, but for humanity, cultural impact overwhelms our genetic roots.

The authors would like to abandon the dichotomy of what's usually referred to as the "nature versus nurture" debate. That's admirable, but not only has that contest been challenged elsewhere, finding anyone adhering to either position as an absolute is difficult, if not impossible. Who claims "genes" are the sole behaviour drive? Not even religions, the most dogmatic element in our society, any longer label infants as "blank slates" to be moulded at will. Individuality and expression may be curtailed, but not constrained. Yet that curtailment, even if only mindless imitation, is the foundation of this book. Instead of the chaos of individual response to environmental pressures, "culture" guides behaviour to the extent that groups become predictable in their activities. For them, "culture" is a sort of behavioural umbrella keeping families and small communities from unravelling the fabric of society.

Richerson and Boyd gather a wide spectrum of studies to erect their cultural edifice. They examine studies of social animals, scrutinise the grim world of economics and wonder how it is that of all species, human beings filled nearly every environmental niche. They accept the complexity of human society as naturally hierarchical. That organisation, coupled with a strong imitative/cooperative sense enabled our species to readily adapt to so many ecological niches. Where some say, "If it works, don't fix it!", Richerson and Boyd counter, "If it works, imitate it!" Human beings, they contend, are better imitators than other species because we can judge long-term impacts of actions. This talent, coupled with language, provides our unique adaptability in varied environments. We can test for success and pass our findings to our neighbours. This gives groups within our species both unique abilities and the means to improve them. Not all of humanity is but one culture. It's a melange of groups, each culture representing a regional or social norm.

"Group selection" is the offshoot of an older, flawed, evolutionary concept - "species selection". With the idea of "species selection" quickly demonstrated as false, group selection arose to replace it. A close look at group selection reveals that it's but another mechanism to keep humanity separated from the remainder of the animal kingdom. If you downplay any similarities between us and other beasts, you are able to retain a "divine spark" or other metaphysical notions for humanity. And only humanity. Richerson and Boyd's use of animal behaviour studies to ameliorate this distinction are a welcome addition to social studies. However, these examples are carefully selected and interpreted by the authors. They aren't set in an evolutionary context, but are given solely as a contrast to the also carefully chosen aspects of human behaviour. The book raises a number of interesting questions, but answers few of them satisfactorily. [stephen a. haines - Ottawa, Canada]

I have to admit that with a title that makes as straighforward a declaration as this one does, I anticipated an imaginative, full frontal assault against the increasing dependence on genetics, DNA, & biology to explain our human nature. Instead, Richerson & Boyd divide the pie pretty equally among genetics, culture, and environment, noting that these three factors are mutually dependent and interactive. Fair enough, but I was disappointed how far they leaned into the genetics camp and how little they credit to human creativity. In fact, they state there really is no such thing as individual creativity but only individuals who are able to carry forth mass cultural trends that have been underway for some time. "Culture usually evolves by the accumulation of small variations" (p. 50). One should note here the early emphasis on the concept of evolution because their book turns out to take Darwin's foundational principles of biological evolution and directly apply them to cultural evolution. Culture, itself, they state, is an adaptation.

Other animals have exhibited certain local behaviour patterns that others have termed cultural, but "only humans show much evidence of *cumulative* cultural evolution. By cumulative cultural evolution, we mean behaviors or artifacts that are transmitted and modified over many generations, leading to complex artifacts and behaviors" (p. 107). In this way, complex artifacts are not "invented by individuals; they evolve gradually over many generations" (p. 107). So human cultural evolution, though not inspired by "great person breakthroughs" is still unique, depending as it does on external memory storage and teaching-learning. I liked this, as I am an educator.

I also liked the point that culture and genes co-evolve. Still it seems to me, they tend to see the human species in a more mechanical manner than is necessarily the case: Everything is ultimately done for survival. Cases where cultural choices like human sacrifice or mass witch-hunts have been undertaken are seen as mistaken attempts at survival. I wonder how this accounts for the suicide cults that have appeared and, not surprisingly, rapidly disappeared? They explain altruism or kindness in the same way, as leading to survival of the group. They even seem to disparage efforts to control population growth. Such efforts, mostly in the middle & upper classes of industrialized countries, are said to be the result of "selfish cultural variants" (p. 169). "Modern low fertility does not maximize fitness" (p. 173). Surely this puts them firmly in the evolutionary biology camp.

The writing is most often turgid & uninspired, with the many examples of cultural continuity or adaptation being local, mundane, & unimpresssive. They end by pleading for the wide acceptance of "a proper evolutionary theory of culture" since that "should make a major contribution to the unification of the social sciences" (p. 246). They call for the development of a mass of quantitative detail on cultural variation to equal the detail found in the study of genetic variation, simply equating the two.

I felt let down at the easy way cultural symbolism & artistic experession were simply dismissed by suggesting a little quatitative analysis would reveal them as simple functionalism. By now I was bored. By the time they snidely state that "So many older scientists try their hand at philosophy that it can practically be regarded as a normal sign of aging" (p. 254), I was glad to finish the book and close it.