Review of Human Natures: Genes, Cultures, and the Human Prospect
by Paul R. Ehrlich
Washington D.C., Island Press, 2000
This is the version originally submitted. It was edited before publication.
‘Human Natures’ reflects Ehrlich’s desire to replace the static notion of one ‘human nature’ with a celebration of the genetic and cultural plurality of ‘human natures’. If his aim is to explore that diversity Ehrlich certainly succeeds. He enlivens explanations of evolutionary theory with stories from his own encounters with chimpanzees, work with fruitflies, and adaptations in bacteria, and moves smoothly from there to explore the fascinating history of hominid evolution. There are descriptions of a wide variety of human cultures and enjoyable stories of his time living with the Inuit in the Canadian Arctic in 1952, trying to learn their language and discovering just how different human natures can be. But this exploration throws up many difficult questions, and not all of them are handled well.
What is racism?
Race is a tricky issue indeed, but perhaps one better left alone altogether than treated as it is here. For a start, the term “racial” is placed in scare quotes and then, in a short section, Ehrlich denies that there are any true racial groups among humans. To support this he relies on some carefully chosen maps demonstrating that variation in skin colour does not correlate with variation in three other traits; average height, hair structure and head shape. These show that “Attempts to treat divisions of humanity based primarily on skin color as natural evolutionary units have always been, and still are, nonsensical.” (49-52). Clearly we cannot usefully divide human beings into a handful of distinct races according to skin colour, but there is much more to race than this, and much smaller groups can be, and are, described as races. So the underlying issue is whether there are group differences in human traits. Ehrlich gives many examples showing that there are. He discusses the geographic distribution of traits such as lactose tolerance, claims that the Inuit have about the largest brains of any living people, and points out that language affects mate choice and therefore leads to differences in gene frequencies between different groups. Are these not, potentially at least, racial differences?
I got the impression that in trying (quite rightly) to avoid making judgements about superiority and inferiority, Ehrlich has tied himself in knots. For example, it is never clear what he means by ‘racism’ – an important problem for a book that tries to combine a moral response to the human situation with scientific understanding. He claims that “… racism can find no support in science”. (p 106). I was shocked at this remark for the following reason. Science could never provide support for racism – at least if racism is understood as valuing some races more highly than others or according them different rights, freedoms or responsibilities. All science can do is to find out whether group differences exist or not. We already know that there are differences in athletic ability between groups; with Kenyans dominating marathon running, West Africans excelling in 100 meter races, and some groups finding swimming almost impossible (Entine 2000, Shermer 2000). If it turns out to be true that some human groups are better at maths, or art or music or learning languages this would still not be support for racism. That is, unless simply believing in the existence of group differences makes you a racist.
I scribbled “Naturalistic Fallacy” in the margin; that famed tendency to confuse ‘is’ with ‘ought’. So I was surprised when, towards the end of the book, Ehrlich himself warns his readers of this mistake, saying “What evolved is neither good or bad: it just is” (p 309). Yet Ehrlich seems unwilling to face the possible ‘just is’ of group differences and consider how we can best respond. This is surely going to be a central challenge for human political systems and societies in the future and Ehrlich does not seem willing to face up to it.
Do we act like our relatives?
Another tangled issue concerns to what extent genes influence behaviour. In Chapter 1. Ehrlich derides such ideas as the genetic tendency of Jews to be moneylenders or Asians hardworking, or the notion that “homosexuality is in the genes” (p 22). He claims there is a ‘fundamental error’ in statements such as “We accept that we look like our parents and other blood relatives; we have a harder time with the idea we act like them.” (from Hamer and Copeland 1998) (quoted on p 7). We do indeed, but should we? Rather than tackling this important issue, Ehrlich seems to reject the very idea that there can be genetically based differences in sexual or other behaviours. Yet as the book goes on, he provides us with wonderfully illuminating examples of how genes influence behaviour; from the edge-pupation behaviour of DDT resistant fruitflies to “Genes predisposing individuals to schizophrenic behavior (the evidence is quite good that such exist)” (p 218).
Ehrlich may be right that “Genes do not shout commands to us about our behavior. At the very most, they whisper suggestions…” (p 7) but even if most of the effects are very small indeed it may yet turn out to be true that, in some tiny measure, people from different racial backgrounds behave a little differently, or enjoy slightly different occupations, or that sexual orientation has a genetic basis, even if there is no single ‘gay gene’. If so, shouldn’t we work to understand, and even enjoy, these differences, rather than push them under the carpet?
Does culture really evolve?
Set against the effects of genes are those of culture, and here we come to what, in my opinion, is the major problem with this book. Ehrlich writes at length about ‘cultural evolution’ but never makes clear what he means by the term – and this is a serious shortcoming for a book that is grounded in evolutionary theory and makes claims to unify ‘genes, cultures and the human prospect’.
The problem is this. There are two major ways in which the term ‘cultural evolution’ is traditionally used. In the first, the term is just a loose descriptive phrase more or less equivalent to ‘cultural change’. The fact that cultures change, develop, and vary is entailed, but no particular mechanism is implied. When the term is used this way there can be no controversy about how cultural change works since no strong claims are made. The only controversy concerns whether it is a appropriate to use the word ‘evolution’ at all, since it has such a precise meaning in biology.
In the second usage, the term is much more specific. It implies not just cultural change, but an evolutionary process driven by a specific mechanism comparable with natural selection. Here there is plenty of substantive controversy over such issues as whether it is useful to think of cultural units as replicators (or indeed to think in terms of units at all), whether variation and selection are major forces in cultural evolution and if so how they work, how cultural evolutionary processes can be modelled mathematically, and whether the genes must forever keep culture on a leash (Aunger 2000, Lumsden and Wilson 1981).
Which does Ehrlich mean? When I began reading the book I assumed that he meant the latter, and that I was in for a challenging exploration of how to apply evolutionary thinking to culture. Ehrlich’s overview of evolutionary biology and human prehistory seemed to be laying the appropriate groundwork. But in the end I had to conclude that he means the former, for he completely fails to commit himself to any kind of mechanism or any theory of how cultural evolution works. Indeed the closest he comes to a definition of cultural evolution is “a gradual change, often into a more complex form, of the body of extragenetic information possessed by humanity.” (p 230). He uncritically treats all of culture as part of the ‘environment’ and does not consider the possibility that culture is an evolving system in its own right. He does point out that historical trajectories show many features in common with biological evolution; giving many interesting examples of historical events, and highlighting the way that both are influenced by isolation and exchange, speciation and extinction. Yet he never explains why the processes look so similar. Does culture evolve by blind variation and selective retention? Is there a cultural equivalent of natural selection? Is culture itself an example of universal Darwinism at work? Ehrlich does not say.
Ehrlich clearly would like answers to such questions. He says:
Evolutionary theory, primarily its biological aspects, converted biology into a coherent discipline. I have long hoped that in the same way, evolutionary theory, primarily its cultural aspects, could do the same for the social sciences. We badly need an evolutionary theory of culture that unites the social sciences … I suspect it will take a revolution by some bright young scholars to develop such a unifying theory. (p231).
Many others hope so too, and some have started on that project, yet Ehrlich barely mentions them. There are probably two main attempts here. One is the long tradition of modelling gene-culture co-evolution by such authors as Cavalli-Sforza and Feldman, Lumsden and Wilson, and Boyd and Richerson (see Durham 1991 for an overview). Ehrlich includes all these in his admirably extensive list of references but barely mentions them in the text. The other is the more recent science of memetics built on Dawkins’s idea of cultural units, or memes, that act as replicators and evolve by the processes of heredity, variation and selection. This attempt Ehrlich dismisses peremptorily in a single footnote as ‘highly speculative literature’. There are certainly problems with the whole idea of memes (Aunger 2000, Blackmore 1999), but at least memetics takes seriously the idea that the whole of human culture might be a vast evolving system, working on the same fundamental principles as biological evolution, and with its own unpredictable (if understandable) dynamics. Using this theory we can ask how and why certain memes survive and reproduce, while others die out, and what the consequences are for the people who carry and copy them. In spite of his ‘long hope’, Ehrlich ignores these attempts while providing us with no theory of his own.
The last chapters deal largely with moral and political issues, and the problems of overpopulation, pollution, the breakdown of small-group living, and the loss of biodiversity. If Ehrlich took seriously the idea of culture as an evolving system, this might be an opportunity to explore how runaway cultural evolution is interacting with the biological system that gave it birth – or how memetic evolution is causing disasters for the biological evolution that made it possible. But since Ehrlich has no theory of cultural evolution he has to be content with a rather general discussion of how biologically evolved human beings are coping with excess food, violence on television and cities built around the automobile.
Although Ehrlich warns us of terrible prospects ahead, and implores us to think harder about human natures and our precious environment, I think he has horribly misunderstood the true situation. One simple sentence says it all “Cultural evolution, unlike biological evolution, is reversible.” (p 303).
Reversible? No evolutionary process is reversible. Yes, species, languages and traditions can go extinct. Yes, new memes can come along that obliterate old ones – like science replacing superstition, effective medicine replacing charms, or cars reducing cruelty to horses, but neither biological nor cultural evolution can go backwards. We cannot take back widespread literacy, the effects of globalisation or the internet. Biological evolution works on whatever material it has to hand. If cultural evolution truly is evolution then the same applies. Moreover, we humans are parts of the process. We cannot somehow step outside of it, or take control, in what Ehrlich calls ‘conscious evolution’. The best we can do is to try to understand how cultural evolution works. In this endeavour Ehrlich does not really help.
Aunger, R.A. (Ed) (2000) Darwinizing Culture: The Status of Memetics as a Science, Oxford University Press
Blackmore,S.J. (1999) The Meme Machine, Oxford, Oxford University Press.
Durham,W.H. (1991) Coevolution: Genes, Culture and Human Diversity. Stanford, Ca., Stanford University Press.
Entine, J. 2000 Taboo: Why black athletes dominate sports and why we’re afraid to talk about it. New York, Public Affairs.
Hamer,D. and Copeland,P 1998 Living with our genes. New York, Doubleday
Lumsden,C.J. and Wilson,E.O. (1981) Genes, Mind and Culture. Cambridge, Mass., Harvard University Press.
Shermer,M 2000 Blood, sweat and fears: Why some black athletes dominate some sports and what it really means. Skeptic, 8:1, 44-53 (see also other articles in this special issue of Skeptic)