Transfer of information concerning distant foods: A laboratory investigation of the ‘information-centre’ hypothesis

When choosing between two novel diets, an ‘observer’ rat (Rattus norvegicus) prefers that diet previously eaten by a ‘demonstrator’ conspecific with whom the observer has interacted prior to making its choice between diets. Demonstrator influence on observer diet selection is maintained even if, during the period of demonstrator-observer interaction, the demonstrator is anaesthetized and a wire-mesh barrier prevents the demonstrator from physically contacting the observer. Demonstrator influence on observer diet choice is blocked by either rendering the observer anosmic or placing a transparent Plexiglas barrier between demonstrator and observer during their period of interaction. We conclude that olfactory cues passing from demonstrator to observer provide observers with information concerning demonstrators' diets and that these olfactory cues are sufficient to bias diet selection by observers. Further, observer rats that have learned the locations at which each of three diets are intermittently available can use information provided by demonstrators to increase foraging efficiency. We discuss the implications of the results both for the ‘information-centre’ hypothesis of the function of mammalian aggregations and for previous studies of social transmission of diet preference in rats.