Monday, January 09, 2006

Cooperation & defection   posted by Razib @ 1/09/2006 03:53:00 PM

Interesting paper in The Journal of Evolutionary Biology caught my attention today, here is the abstract:

The Prisoner's Dilemma (PD) constitutes a widely used metaphor to investigate problems related to the evolution of cooperation...Recently, compelling evidence has been accumulated on the strong heterogeneous nature of the network of contacts between individuals in populations. Here we describe the networks of contacts in terms of graphs and show that heterogeneity provides a new mechanism for cooperation to survive. Specifically, we show that cooperators are capable of exploring the heterogeneity of the population structure to become evolutionary competitive. As a result, cooperation becomes the dominating trait in scale-free networks of contacts in which the few highly connected individuals are directly inter-connected, in this way contributing to self-sustain cooperation.
Here is the full PDF free.

The evolution of cooperation and biological sociality was the central problem which haunted W.D. Hamilton during the first part of his career. Hamilton Rule, B*r > C (benefit to the other multiplied by the genetic relatedness being greater than cost to self), pithily expressed the logic behind kin selection and inclusive fitness. In this way the genetic rationale behind the evolution of altruism could be modeled by selfish gene level thinking. Robert Trivers' reciprocal altruism was a model which broke out of a gene-centered box, as did Hamilton's later work in collaboration with Robert Axelrod which used a more game theoretic paradigm, and all the various iterations of tit-for-tat. David Sloan Wilson has attempted to resurrect multi-level selection, and anthropologists Peter Richerson and Robert Boyd have thrown every tool including the kitchen sink at the "problem" of human culture.

In regards to the complexity of human societies it seems, to me, that using any one particular line of conceptualization (i.e., kin selection, reciprocal altruism, rational choice, etc.) will fail to capture the textured complexity of social processes. In a similar fashion behavior genetics alone, or evolutionary psychology alone, will fail to satisfactorily model humanity as it manifests itself. Variation as a function of time and space seems to be characteristic of our species and that is a shame for grand meta-narratives. I have already noted before that the literature over the past few years has been suggesting strong caution at the utilization of kin selection even among hymenoptera, the taxon which Hamilton used to empirically test his a priori models (hymenoptera are ideal because sisters are more closely related to each other than they are to their own offspring). Of course, this does not mean that we give up and put our faith in gods and mysterious essences which generate order from the chaos.

Update: To get an overview of the controversy over kin selection in the context of eusocial insects, see this paper Kin selection is the key to altruism (PDF).