Hello folks, in this unit we’re going to look at two extremely simple models of a rather complex phenomenon; that is, the phenomenon of cooperation in social systems. How is it that intrinsically selfish individuals living in a society, or any kind of social group, learn or find a way to cooperate in order to increase the benefit for all members of the group? That’s what these models are about. We’re going to look at two of the most famous of such models, the Prisoner’s Dilemma model and the so-called El-Farol Model. Let’s get started. The existence of cooperation is often a mystery, in biology and in the social sciences. The main assumption of natural selection, and much of social and economic theory is that individuals act in order to maximize their own so-called “utility” which might mean: their reproductive success, their profit, their happiness, or what have you. In short, individuals are assumed to be selfish and yet the phenomenon of cooperation and even altruism are evident at all levels of biology and in society. How does this come about? So this leads to some questions. How is it that cooperation comes about in biological populations? In communities? In societies of selfish individuals? And how does it persist? And finally, how can we create conditions to make it happen? It’s very difficult to design experiments to explore these questions. So, people have, especially in the field of complex systems, largely looked at these kinds of questions through the use of simplified computer models which often are called “idea models”. An idea model is an idealized model of a phenomenon that shows that a proposed mechanism might be plausible, or two explore general mechanisms that underlie behavior, explore the effects of different kinds of environments, different kinds of parameters on the behavior, et cetera. In this unit, we’re going to take a quick tour of two classic idea models in this area. First, the Prisoner’s Dilemma model, which has been explored in great detail by political scientist Robert Axelrod and the so-called El-Farol problem which was devised by economist Brian Arthur. Really, this is just going to scratch the surface of idea models addressing questions about cooperation in social systems. But hopefully, this will give you a flavor of the kinds of things that people have done in the past and I’ve put a number of references up on our course materials page to get you started with some reading with some reading about things that have been going on more recently in this area.