Effectiveness of familiar kin and unfamiliar nonkin demonstrator rats in altering food choices of their observers

In a series of three experiments, we examined the prediction from formal theories of the evolution of social learning that, all else being equal, animals should be more likely to learn socially from familiar individuals or kin than from unfamiliar individuals or nonkin. In all three experiments, contrary to prediction, naive Norway rats, Rattus norvegicus, were marginally more likely to learn to prefer a food eaten by an unfamiliar than by a familiar conspecific demonstrator. The finding that, when given a choice, naive rats spent more time near unfamiliar than near familiar demonstrators offers a possible explanation for the observed greater influence of the former compared to the latter on the food choices of their observers. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.