Error, population structure and the origin of diverse sign systems.

Evolutionary models of communication are used to shed some light on the selective pressures involved in the evolution of simple referential signals, and the constraints hindering the emergence of signs. Error-prone communication results from errors in transmission (in which individuals learn the wrong associations) and communication (in which signs are mistaken for one another). We demonstrate how both classes of errors are required to generate diversity and subsequently impose limits on the sign repertoire within a population. We then explore the influence of geographic structuring of a population on the evolution of a shared sign system and the importance of such structure for the maintenance of sign diversity. Deceit tends to erode conventional signs systems thereby reducing signal diversity, we demonstrate that population structure can act as a hedge against deceit, thereby ensuring the persistence of sign systems. Copyright 2000 Academic Press.