Limits on social influence on food choices of Norway rats

We examined social influences on food choices of Norway rats choosing between pairs of diets that differed in their relative palatabilities. We found in two experiments that prior interaction with a demonstrator rat fed either a cayenne-flavoured diet (experiment 1) or a cinnamon-flavoured diet (experiment 2) significantly affected the observer rats' intake of their respective demonstrators' diets. However, as the amount of cayenne pepper in the cayenne-flavoured diet was increased, so that it became increasingly unpalatable relative to a cinnamon-flavoured alternative diet (experiment 1), the effects of demonstrator rats on their observers' intake of the cayenne flavoured diet diminished. Similarly, as we added sugar to a cinnamon-flavoured diet, so that it became increasingly palatable relative to an alternative cocoa-flavoured diet (experiment 2), the effects of demonstrator rats on their observers' choices between the cinnamon- and cocoa-flavoured diets diminished. Taken together with findings in the literature, the present results suggest that the greater the difference in a subject's affective responses to two stimuli, the less the effect that social influences have on its responses to those stimuli. (C) 1998 The Association for the Study of Animal Behaviour.