IGERT Program in Evolutionary Modeling

Sender-Receiver games are simple, tractable models of information transmission. They provide a basic setting for the study the evolution of meaning. It is possible to investigate not only the equilibrium structure of these games, but also the dynamics of evolution and learning -- with sometimes surprising results. Generalizations of the usual binary game to interactions with multiple senders, multiple receivers, or both, provide the elements of signaling networks. These can be seen as the loci of information processing, of group decisions, and of teamwork.

The adoption of agriculture at the expense of hunting and gathering was the dramatic precondition for all of modern civilization. Recent data suggest, however, that, as a result of this transition, humans at first became more prone to disease, lived shorter lives, were less well-fed and were smaller in stature. Why then would individuals who had the choice of the two economic systems have chosen agriculture?

The social transmission of behavior is no doubt an adaptation. However, learning from people other than one's parents may favor the evolution of "parasitic" beliefs that channel individual resources that could be spent on survival and reproduction into spreading the belief itself. These risks may reduce the adaptive value of non-parent transmission. I model the evolution of a preference for learning from parents, when parasitic beliefs are possible. Learning from parents can inoculate both the individual and the population from the rise and spread of parasitic ideas.

Evolutionary models for reproductive decision-making have not fared well in explaining fertility transitions. Such models typically make the implicit assumption that all births are substitutable, however, this is only true under extremely restrictive demographic circumstances. I develop a method for measuring the marginal value of fertility based on an extension of the Leslie matrix to individual birth histories. The cumulative fitness function with parity is concave, indicating diminishing marginal returns to higher-order births.