Innovation and social transmission in animals: A cost -benefit model of the predictive function of social and nonsocial cues.

Abstract

This thesis presents a new approach to understanding social transmission among nonhuman animals. Drawing on basic principles of behavioral ecology, I suggest that animals are likely to test new behaviors when the payoffs for doing so exceed the payoffs for engaging in familiar behaviors. If true, expected utility theory and Bayesian decision making models can help us predict how confident of success an individual must be before trying a new behavior. When the probability of a positive payoff exceeds the predicted threshold, the individual should attempt the new behavior. Otherwise, the individual should refrain from experimentation. Animals can assess the probability of a positive payoff by attending to social and environmental cues. Reliable cues provide animals with the required level of confidence. Animals should heed reliable cues, and they should depend exclusively on social cues when they are the only reliable cues available. I investigate the implications of this cue reliability approach for our understanding of decisions about (1) sampling new foods, (2) responding to potential predators, and (3) responding to unfamiliar conspecifics. I suggest that once we understand the expected payoffs associated with such decisions, we can use this information to test for the existence of traditions among wild populations. I also offer a formal analysis of social cue reliability and present a new model of the evolution of teaching that derives from the work of Hamilton (1964) and Trivers (1974). Although previous research provides some support for the cue reliability approach, more studies are needed to test its quantitative predications. I report the results of three experiments that examine how animals respond to reliable and unreliable cues. As predicted, the results indicate that animals discriminate between reliable and unreliable cues. The results also suggest that animals depend more on social cues when nonsocial cues are unreliable.