Not by Genes Alone: How Culture Transformed Human Evolution. Peter J. Richerson and Robert Boyd. University of Chicago Press, Chicago, 2005. 332 pp. $30.00 (ISBN 0226712842 cloth).
Why are Peter Richerson and Robert Boyd so against memes? This is the question that baffled me all the way through this excellent book. Writing in a much more accessible form than they have before, Richerson and Boyd lay out their case for the role of culture in shaping the human mind and behavior. They describe vivid examples, from the conflict between the Nuer and Dinka peoples in Sudan to the gift exchange systems of the !Kung San, and from altruism within and between groups to the persisting isolation of the Hutterites and Amish.
Richerson and Boyd's is a strong form of gene–culture coevolution theory that emphasises population-level thinking. They dub the prevailing approach in evolutionary psychology the “big mistake hypothesis” because of the way it deals with maladaptive human behavior. For example, humans eat too much sugary food, spend enormous amounts of resources on education and learning, and are very poor at converting wealth into grandchildren. All this is clearly mal-adaptive from the gene's-eye point of view—and the way theories explain mal-adaptation is critical.
Rather than being a big mistake, Richerson and Boyd argue, such behavior is an unavoidable by-product of cumulative cultural adaptation. They make a good case, based on their extensive modeling studies, that imitation evolved because it helps people adapt rapidly in a wide variety of environments. Once it evolved, however, this meant that maladaptive ideas were let in—that is, ideas whose content helps them to spread even though they do not enhance the genetic fitness of their carriers. A modern example is the childless professional who succeeds culturally by spreading ideas to students, colleagues, or employees. Selection cannot eliminate such maladaptive variants because adaptive information is costly to evaluate—hence Richerson and Boyd's own theory, the “costly information hypothesis.”
This sounds like a memetic argument. The theories, practices, and behaviors of these childless professionals are all selfish memes that spread for their own benefit. So why don't Richerson and Boyd think of it that way? In fact, they do discuss memes, and they even use the phrase “selfish memes” a few times, but in the end they reject memetics.
The population approach, they say, does not imply that cultural evolution is analogous to genetic evolution; nor does it depend on “discrete, faithfully replicating, genelike bits of information.” I quite agree, but then, so would Dawkins and most other memeticists. In his 1976 book The Selfish Gene, Dawkins did not invent the term “meme” to be an analog of “gene” but rather to provide an example of another replicator, that is, another example of information that is copied with variation and selection. So, although there may be interesting analogies between genes and memes, this is not the point. The point is that both are replicators, which means that some analogies may be close, but others will not. That there are significant differences between genes and memes, and between cultural and genetic evolution, is not a valid argument against memetics.
Nor do replicators have to be “discrete, faithfully replicating, genelike bits of information.” Dawkins long ago pointed out that the copying fidelity of most memes is very low, there is often no right way of deciding where one meme begins and another ends, and most memes do not appear to be particulate—themes later taken up by both Dennett (1995) and me (Blackmore 1999). This does not disqualify songs, stories, scientific theories, or technologies from being replicators; it simply means that these memes are rather poor-quality replicators—as we might expect from an evolutionary process that began only a few million years ago, at most.
Could it be that Richerson and Boyd are merely rejecting the word “meme” because of its popular connotations, when their theory is really equivalent to memetics? I have wondered about this for many years, because it is clear that along the spectrum of gene–culture coevolution theories, that of Boyd and Richerson has always been the closest to memetics; that is, they have come very close to treating their cultural variants as true replicators that evolve in their own way, and without being firmly held on the genetic “leash” postulated by E. O. Wilson. The answer depends on whether Richerson and Boyd think that cultural variants are replicators or not. In this book we have the answer, and it is “no.”
In a section entitled “Cultural Variants Are Not Replicators,” they repeat the false claim that copying must be perfect for a replicator to count as such, and explore interesting arguments about the many and varied mechanisms of cultural transmission. For them the peculiarities of biased transmission, behavioral attractors, and error-prone imitation are reasons to reject the idea of culture as a system of replicators, whereas for me memes are obviously information that is copied with variation and selection; the real question, then, becomes an empirical one. How high does the fidelity have to be for an evolutionary process to get off the ground? If human imitation is good enough, then we should be justified in treating memes as replicators, shouldn't we?
You may be wondering whether this is all just quibbling over words, but I think not. Richerson and Boyd's theory really is different from memetics and has correspondingly different implications for both our past and our future. Although Richerson and Boyd describe humans and our culture as being like obligate mutualists, they still maintain that “culture is on a leash, all right,” even if the dog on the end is big and clever. This is because, for them, “culture is an adaptation.” In other words, culture was adaptive for human genes, it evolved for that reason, and it has persisted for that reason, in spite of including some maladaptive elements. In this respect, the authors fit Dawkins's complaint about his 1970s colleagues:” In the last analysis they wish always to go back to ‘biological advantage’” (Dawkins 1976, p. 193). This is, in the end, the fundamental difference—where the power lies.
According to memetic theory, memes are true replicators and have the same replicator power as genes. Culture is not an adaptation and never was. Rather, imitation was an adaptation that had unintended consequences: It let loose a new replicator—the behaviors, skills, and artifacts that people copied. These memes then began evolving for their own benefit, because that is what replicators do, creating a new process that would, as Dawkins emphasized, “in no necessary sense be subservient to the old” (Dawkins 1976, p. 194). Culture could have killed us all off. Indeed it is still possible that it killed off other species that tried the imitation experiment. We simply do not know enough about the evolution of our hominid relatives to be sure. It is certainly possible, and indeed quite likely, that it will kill us all off in the near future. And as for that future, Richerson and Boyd do not venture their predictions, but memetics predicts an ever increasing information explosion as memes proliferate along with ever better meme machines to replace the phones, faxes, computers, and World Wide Web of today.
Which theory is right? Both are testable; we will wait and see. Meanwhile this book provides an excellent account of Richerson and Boyd's theory, and is a must-read for anyone interested in gene–culture coevolution.
