The Social Transmission of Food Preferences in Small Colonies of Norway Rats

Abstract

The present research investigates the social transmission of food preferences in small colonies of domestic rats. In Experiment 1, four demonstrator rats were poisoned for consumption of a particular flavored diet and placed in a floor enclosure with a choice between the averted diet and an alternative diet. These original demonstrators were replaced one by one each 24-hr over a period of 4 days with naive subjects. The original demonstrators effectively transmitted a preference for the alternative diet to the naive replacements, as these replacements exhibited a preference for the alternative diet for a period of 4 days following the departure of the final demonstrator. Employing essentially the same methodology as that used in Experiment 1, videotape analysis of the feeding behavior of subjects on the sixth day (zero original demonstrators, four naive replacements) of Experiment 2 revealed no significant difference in the food choices of the first, second, third and fourth replacement subjects, indicating that naive replacements became effective demonstrators following interaction with original demonstrators. Random placement of the food bowls each day during Experiment 3 revealed that the social transmission of food preferences from original demonstrators to naive replacements can persist in the absence of excretory cues around a particular feeding site. In Experiment 4, removal of demonstrators from the floor enclosure during periods in which foods were available there for replacement subjects to choose between revealed that naive observers could obtain sufficient information from demonstrators during non-consumption periods to guide their food choices. Observers in Experiment 4 exhibited a preference for their respective demonstrators' diets when presented a choice between their demonstrators' diet and an alternative diet in the absence of demonstrators. In the General Discussion, variables were discussed that might modify the strength of socially transmitted food preferences in rats and could be examined in future research using the present paradigm.