Rats’ responses to a moving object related to food or water: A behavior-systems analysis

The present experiments compared rats’ responses to a moving object (a rolling ball bearing) related to either food or water under both Pavlovian and operant contingencies. In Experiment 1, food-restricted rats contacted food-related bearings more frequently and with more complex response patterns than water-restricted rats contacted water-related bearings. Food-related contacts occurred with shorter latency, longer average duration, and increased likelihood of dig, carry, and chew. Experiment 2 revealed that once contact with the bearing had been established, its form persisted despite changes in the type of reward and restriction. In Experiment 3, rats that were simultaneously food and water restricted learned to discriminate between painted and unpainted bearings related to food versus no food, water versus no water, and food versus water. Again, food-related bearings produced more complex, although not more frequent, interactions than did water-related bearings. In none of the experiments did rats lick the ball bearing related to water. The results supported a behavior-system approach, but not the stimulus-substitution or arbitrary-operant accounts of conditioned-response topography.