Carl T. BergstromWashington University

Over the past 3.5 billion years, living organisms have evolved to acquire, store, analyze, and transmit information. This information processing capacity has allowed organisms to build up increasingly complex social organizations predicated on the effective coordination and cooperation. Coordination and cooperation in turn require honest communication among the participants in a social group. To function effectively, however, social systems need to overcome various strategic issues surrounding the threat of deception: Why do agents share information even when their interests conflict? Why don’t cheaters exploit and undermine communication by sending deceptive signals? How do communicating parties avoid eavesdropping and signal tampering? Such problems arise among the individuals within complex animal societies such as baboon troops, cooperatively nesting birds, and social insects, and also among the cells within any single multicellular organism. I argue that the threat of deception can be broken down into at least two categories: 1) cases in which the legitimate members of the social institution have some overlap in interests, but they also have individual incentives for deception, and 2) cases in which non-members of the social organization attempt to parasitize and exploit the system by subversion and other forms of trickery. We see the former category in the evolution of mate-choice signals; we see the latter in the evolution of immune strategies to deal with pathogens. I will discuss the problem of deception in biological systems, describe how these problems can be formalized using mathematical game theory, and outline some of the strategies that organisms use to overcome these problems.