The economics of animal communication: theory and experiments integrating receiver choice and strategic signal reliability

Abstract

This research centers on two themes fundamental to communication, signal reliability and receiver tolerance of imperfect reliability (abbreviated as receiver tolerance). Focus on signal reliability tends to dominate research on signaler-receiver interactions, but represents only half of the signaling dyad. Understanding why signals are reliable and why receivers follow imperfect reliability are equally important; I argue the combination of reliability and receiver tolerance to ultimately determines the form and stability of signaler-receiver interactions. To explore these themes, I first developed a model of signaling interactions that combines aspects of models of receiver choice and signal reliability. The results highlight the co-importance of receiver tolerance and reliability enforcement mechanisms (such as signal cost). To experimentally test the model predictions, I developed a novel laboratory signaling game that allows control over theoretically important variables (such as the level of conflict between the signaler and receiver). The game placed blue jay subjects (Cyanocitta cristata) in a signal-response game played for food rewards. A series of these signaling-game experiments demonstrate the effects of signal cost on signal reliability (or honesty) and show the extent to which uncertainty in the environment generates receiver tolerance. Signal cost is an important topic in signaling theory, but lacks direct empirical support. I show that high signal cost does increase honesty under conditions of conflict, but also that cost is unnecessary in mutualistic conditions. I also show that receiver tolerance increases when environments are uncertain (to the point that receivers are gullible), and that signalers are sensitive to the level of receiver tolerance – exploiting tolerance when signaler and receiver interests conflict. Taken together, these models and experiments establish the value of considering both signal reliability and receiver tolerance.