Behavioral Contrast in a Group Foraging Paradigm

Two experiments examined multiple schedule behavioral contrast in a group foraging paradigm. Groups of five rats foraged simultaneously in a large open field apparatus with two feeding stations. Food pellets were delivered at each of the feeding stations on multiple Variable Time schedules. As predicted by both the matching law and the ideal free distribution, the relative distribution of behav-ior between the two feeding stations roughly matched the relative rate of food delivery at the feeding stations. These differences were reflected in both the behavior of individual animals and in the behav-ior of the group. Positive behavioral contrast was found in Experiment 1, evidenced by an increase in the frequency of response in one component produced by a decreased rate of food delivery in the other component. Negative behavioral contrast was found in Experiment 2, evidenced by a decreased frequency of response in one component produced by an increased rate of food delivery in the other component. Interestingly, there was virtually no correlation between the behavior of an individual animal and the number of pellets consumed by that animal. The present results support other attempts to compare the matching law to the ideal free distribution. The data also show that behavioral contrast is predicted by both models and in fact occurs in ways consistent with both models. Contrast effects come in many varieties. Following Crespi’s (1942) classi