We investigate the evolution of signal-meaning associations (symbols and words) when there is common interest as well as a conflict between communicating individuals. Taking alarm calls as an example, we show that if the temptation to cheat is low, a single signal is used in the population. If the temptation increases cheaters will erode the credibility of a signal, and a honest mutant using a different signal (`a secret code') will be very successful until this, in turn, is eroded by cheaters. In such a fluctuating the system, signal-meaning associations are not constant but fluctuate in time and space. When the temptation to cheat is too large, no honest communication can maintain itself in a Tower of Babel of many signals. We discuss our analysis in the light of the Green Beard mechanism for the evolution of altruism.
More info and some simulations can be found here.
Update September 27, 2002 by Minus