MULTIPLE MODELS IN SOCIAL TRANSMISSION OF FOOD SELECTION BY NORWAY RATS, RATTUS-NORVEGICUS

To investigate how an observer rat integrates multiple diet information from several demonstrator rats, an observer rat was allowed to interact with a group of four demonstrators simultaneously for 30 min, and was then offered a two-choice preference test. Each demonstrator group member had previous experience with one of two different flavoured diets. Based on different combinations of dietary experience of demonstrators, five types of demonstrator groups were formed. The relationship between the dietary preference of an observer and the ratio of the different demonstrator types in the group was investigated with Sprague-Dawley rats (females only) and Long-Evans rats (with both sexes and two age classes) in two experiments. The preference response differed significantly between observers of five demonstrator groups, and the difference increased in proportion to the ratio of the different demonstrator types. The results suggest that direct bias could be involved in the social transmission of food selection by Sprague-Dawley rats, but no bias is involved in the Long-Evans. The strength of social transmission did not show sex and age variation. Nevertheless, the baseline innate preference seemed to be lower for male than female rats. © 1992.