Food preference, keeper ratings, and reinforcer effectiveness in exotic animals: the value of systematic testing.

Food preference describes the behavior of selecting between items for consumption; reinforcer effectiveness is the functional effect of that item in controlling behavior. Food preference and reinforcer effectiveness were examined in giant pandas (Ailuropoda melanoleuca) and African elephants (Loxodonta africana). A pairwise comparison between food items was used to assess food preference. High-, moderate-, and low-preference items were selected and tested for reinforcer effectiveness. High-preference items controlled behavior more effectively than less-preferred items. Caregiver ratings of food preferences were also collected for each subject, but these reports did not necessarily coincide with actual subject preferences. Caregiver ratings correlated with the food preferences of only 1 individual of each species; thus, preferences of 1 nonhuman animal may be falsely generalized to all animals of that species. Results suggest that food choice and reinforcer effectiveness should be investigated empirically and not rely on anecdotal reports.