Monday, May 01, 2006

Evolution of Cooperation   posted by DavidB @ 5/01/2006 05:09:00 AM

Readers of John Hawks will already have seen his account of a recent paper on the evolution of cooperation.

The details are:

Mikhail Burtsev and Peter Turchin: 'Evolution of cooperative strategies from first principles', Nature, vol. 440, 20 April 2006, 1041-1044.

Here is the abstract:

One of the greatest challenges in the modern biological and social sciences is to understand the evolution of cooperative behaviour. General outlines of the answer to this puzzle are currently emerging as a result of developments in the theories of kin selection, reciprocity, multilevel selection and cultural group selection. The main conceptual tool used in probing the logical coherence of proposed explanations has been game theory, including both analytical models and agent-based simulations. The game-theoretic approach yields clear-cut results but assumes, as a rule, a simple structure of payoffs and a small set of possible strategies. Here we propose a more stringent test of the theory by developing a computer model with a considerably extended spectrum of possible strategies. In our model, agents are endowed with a limited set of receptors, a set of elementary actions and a neural net in between. Behavioural strategies are not predetermined; instead, the process of evolution constructs and reconstructs them from elementary actions. Two new strategies of cooperative attack and defence emerge in simulations, as well as the well-known dove, hawk and bourgeois strategies. Our results indicate that cooperative strategies can evolve even under such minimalist assumptions, provided that agents are capable of perceiving heritable external markers of other agents.

I have posted previously on the subject of cooperation, or the related problem of altruism, and I am sceptical about the realism of much of the game-theoretical work: for some criticisms see here.

However, the paper by Burtsev and Turchin does have some promising features. One is that it allows for a wider range of strategies than most previous models. Strategies are allowed to evolve by natural selection from more basic behavioural variables. The other important feature is that individuals are allowed to recognise the degree of 'similarity' of other individuals to themselves. It is found that this influences their behaviour. In this model the only source of 'similarity' is genetic relatedness, but the authors say that they intend to extend their approach to take account of cultural transmission.

As I've probably said before, I think there is a crying need for someone to give an expert but non-technical presentation of all this recent work to a wider public. (I'm thinking of something like Matt or Mark Ridley's level of popularisation.) The 'someone' would need to be an expert in game theory (so it ain't me, babe), knowledgeable about both anthropology and evolutionary theory, a very clear writer, and capable of being impartial between the various models and theories, as well as being objective about the whole game-theoretical approach (which excludes many of the direct participants in this work!) John Maynard Smith could have done it, but alas, it won't be him.