After recent discussion of cultural evolution I realised that I didn’t know much about memes, so I set myself the penance of reading Susan Blackmore’s The Meme Machine.
It turned out to be a painless penance, as the book is well written and full of interesting ideas. Blackmore doesn’t overstrain the analogy between memes and genes – in fact, she stresses the differences more than the similarities. She believes that the ‘key innovation’ of the human species is the ability to imitate. True imitation is rare among non-human animals, and the range and quality of human imitation are unique. The ability to imitate presumably first evolved because it conferred a genetic advantage, but once the ability had emerged, it created a new selective environment in which genes and memes co-evolve. Blackmore also emphasises that sexual selection would favour the best imitators, and argues that ‘the specific nature of the memes of the time would determine which genes were more successful. The memes began to force the hand of the genes’ (p. 79). Using this concept of ‘memetic
driving’ she attempts to explain the main features of human evolution, including the expansion of the human brain and the emergence of complex language. She goes on to consider major areas of cultural evolution such as sex roles, altruistic behaviour, and religion. Finally, she has some bold ideas about the construction of personality and the ‘self’ as a product of competition and selection among memes in the individual brain.
For all that, I still don’t find the book convincing! This is partly because the analysis of specific cultural traits is naive and superficial. For example, before discussing the celibacy of the (Catholic) clergy in print, one should at least read some ecclesiastical history to find out when, where, and how the rule of celibacy was established. In fact, it wasn’t generally enforced until the eleventh century, as part of the medieval Papacy’s campaign to impose central control over church appointments and property. This had more to do with politics and economics than anything covered by ‘memetics’.
Blackmore’s arguments about ‘meme-gene co-evolution’ are also sketchy and hand-waving. Her rhetoric implies that memes ‘drive’ the genes contrary to natural selection, but if this is really what she means, she needs to spell the process out more clearly. There is no problem if she just means that the products of imitative behaviour create new selective pressures for the genes, any more than there is a problem in the fact that once birds start making nests this imposes new selective pressures for nest-building. But she seems to intend more than this. She relies heavily on sexual selection (by female choice) to promote the ‘meme-favoured’ genes, but the theory of female choice is notoriously tricky (see the discussions in P. Bateson (ed.) Mate Choice, and M. Andersson, Sexual Selection). And there is no guarantee that what works with genes carries over to memes.
Consider especially the ‘Fisher’ process of evolution by female choice. First, we assume that a small but significant proportion of females have somehow acquired a genetically-based preference for males with a certain genetically-based trait. Provided there is some degree of polygyny in the mating system, the preference will give that trait a selective advantage. Females who mate with the favoured males will have offspring who often have genes both for the female preference and for the favoured male trait. The male offspring will often carry (but not express) the gene for female preference and pass it on to their own daughters. And since males with the favoured male trait have higher fitness (and therefore more daughers) than those who do not, the gene for female preference will increase in frequency. And so on, and so on.
But a crucial part of this process depends on males carrying unexpressed genes for female behavioural traits. While this is no problem for genes, it is far from clear that the same applies to memes. Genes can be recessive or sex-limited (expressed in only one sex), which on the face of it is impossible for memes. Why should women have the same memes for sexual preference as their fathers’ mothers, and not those of their own mothers or their mothers’ mothers? Yet Blackmore discusses the ‘Fisher’ process without showing any awareness of these problems, and I am not convinced that she has thought the implications through in detail.
Still, it’s an important book, and well worth reading. Overall, it left me with the feeling that memes do need to be taken seriously, but only as one aspect or dimension of cultural evolution. I suggest that in looking at any cultural trait we should consider at least the following aspects of it:
Historical: what do we know about how the trait has actually emerged and developed?
Economic: what are the costs and benefits of the trait, and to whom?
Evolutionary psychology: how does the trait relate to our ‘basic instincts’, such as sex and status?
Social system: how does the trait fit in with other aspects of the society in question? E.g., if the trait is dowry-giving, one needs to look at the whole system of marriage, property and inheritance, but without the ‘functionalist’ assumption that the trait must serve some purpose in maintaining the system.
Memetic: what characteristics of the trait may enhance its memetic survival and replication? What advantages may it have over rival memes?
DAVID BURBRIDGE
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