The evolution of relevance

With human language, the same utterance can have different meanings in different contexts. Nevertheless, listeners almost invariably converge upon the correct intended meaning. The classic Gricean explanation of how this is achieved posits the existence of four maxims of conversation, which speakers are assumed to follow. Armed with this knowledge, listeners are able to interpret utterances in a contextually sensible way. This account enjoys wide acceptance, but it has not gone unchallenged. Specifically, Relevance Theory offers an explicitly cognitive account of utterance interpretation that presents a radical challenge to the neo-Gricean paradigm. Evolutionary considerations are one way in which we can choose between competing theories. A simple game-theoretic model of the evolution of communication is presented, and it is used to derive a number of basic qualities that will be satisfied by all evolved communication systems. These qualities are observed to precisely predict the foundational principles of Relevance Theory. The model thus provides biological support for that enterprise in general, and for the plausibility of the cognitive mechanisms that it describes in particular.