Making sense in the light of evolution

Abstract

Sense and Nonsense. Evolutionary Perspectives on Human Behaviourby K.N. Laland and G.R. Brown. Oxford University Press, 2002. £16.99 hbk (ix ? 369 pages) ISBN 0 19 850884 0Readers of TREE would probably agree with Dobzhansky's famous adagium that ‘Nothing in biology makes sense except in the light of evolution’. If this is so, then it would also apply to human behaviour, and that is what Sense and Nonsense is about. However, does Dobzhansky's statement itself make sense? I think that it should be read as a slogan to enhance the cultural fitness of Darwin's evolution meme, because, as a scientific statement, I fear that it does not fall into the first category of the main title of this book. At least since Tinbergen's [1xOn aims and methods in ethology. Tinbergen, N. Z. Tierpsychol. 1963; 20: 410–433CrossRefSee all References][1] equally famous formulation of the four main questions in behavioural biology, we know that (human) behaviour can make sense also in the light of function, development and causation. Looked at in this way, an important problem for the five different schools of thought discussed in this book (human sociobiology, human behavioural ecology, evolutionary psychology, memetics and gene-culture co-evolution) is: how can we make sense of human behaviour in the light of evolution? At various points in the book, it is said that human behaviour is ‘made sense of’, ‘interpreted’, ‘understood’, or even ‘explained’ by means of an evolutionary approach. This is treacherous ground, and the issue is dealt with in different ways by the advocates of the different approaches. The most extreme case is that of the more outspoken proponents of evolutionary psychology, in particular Cosmides and Tooby [2xFrom function to structure: the role of evolutionary biology and computational theories in cognitive neuroscience. Cosmides, L. and Tooby, J. : 1199–1210See all References][2], who suggest that the mechanisms of the human brain and cognition can only make sense (i.e. can be studied/explained/understood) in the light of evolution. According to these evolutionary psychologists, knowledge of the selection pressures that were affecting the behaviour of stone-age man is essential for an understanding of the brains and minds of contemporary humans.We only need to go back to Tinbergen to see the fatal flaw in this reasoning, namely the assumption that function can explain mechanism. The evolutionary history of a behaviour or cognitive system, or indeed the function it might have had during the Pleistocene (which is basically what Cosmides and Tooby are suggesting) simply cannot explain the mechanisms of brain and cognition in modern humans or other animals. Obviously, an evolutionary analysis of behaviour is just that (i.e. it can give us insight into its evolutionary history). In Laland and Brown's excellent critique of evolutionary psychology, they add other objections, such as a questioning of the adaptive lag, and the risk of ‘evolutionary story telling’ when one is hazarding a guess at selection pressures in a fairly arbitrarily chosen era of human history.Human behavioural ecology is basically behavioural ecology applied to anthropology, where the behaviour of usually pre-industrial human societies is interpreted as being adaptive. No risk here of confounding function and mechanism. This is perhaps why human behavioural ecologists received so much flak from their evolutionary psychologist colleagues, as we can read in this book. It would seem that, for the evolutionary psychologists, human behavioural ecology has too much adaptiveness and not enough adaptedness, as is explained very clearly by Laland and Brown. What is missing in all these approaches is an analysis of the evolution of human culture as separate from genetic evolution, and that is where memetics and gene-culture co-evolution come in. It turns out that ‘memetics’ is an attempt to turn Richard Dawkins’ idea of the meme into a science. Although the authors are clearly sympathetic with this paradigm, they are forced to conclude that, currently, ‘Memetics is a social club in which Dawkins and Dennett fans put on their meme's-eye view goggles and entertain each other with fanciful evolutionary stories’. Later we learn that the gene-culture co-evolution meme is not faring much better, mainly because of its forbidding abstract mathematical modelling approach. I did find the authors’ review of this young science as a way of analysing the evolution of human culture very convincing. Overall, the authors’ succeed in giving a balanced view of the rival paradigms, which will have been difficult given that Laland himself is an important player in the gene-culture co-evolutionary approach.This is a superb book that I can recommend to anyone interested in these issues. It is a vehicle for a set of memes that I hope will invade the brains of many students of behaviour, ecology and evolution, and of their teachers too, for that matter.