Conspecific Influences on Diet Choice in the Norway Rat (Rattus Norvegius): The Role of Early Social Isolation

Abstract

<p> There is a large literature discussing social influences on diet choices in rats. However, the ontogeny of social influences on diet choices is poorly understood. Early experiences have dramatic affects on the development and expression of future behaviors.</p> <p> The present research investigates whether early social experience altered the susceptibility to social influences on diet choices in juvenile Norway rats (R. norvegicus). Interactions with dam and siblings between parturition and weaning are prominent features of early rats development. It was hypothesized social behavior developed during this period and rearing pups in social isolation would disrupt the development of normal social behaviors.</p> <p> Conspecifics influence the diet preferences of others by socially interacting. The first experiment investigated whether demonstrators could influence diet choices of rats with no social experience. In terms of diet preferences, demonstrators influenced both normally reared rats and rats reared in social isolation.</p> <p> Interactions with conspecifics and exposure to diet odors without social contexts influenced the diet choices of 21 day old pups. Only interactions with conspecifics influenced diet choices of 28 day old rats. Rearing rats in social isolation may delay the onset of social specificity and the results of experiment 1 may have been the product of two different mechanisms. The second experiment investigated whether rats reared in social isolation attended to socially specific cues or to general olfactory cues. Exposure to flavored diets in a non-social context did not influence diet choices of rats reared in social isolation or normally-reared rats. Thus early social interactions do not appear to be necessary for demonstrator rats to influence the diet choices of other rats.</p>