Motivational properties of cues following blocking of acquisition and extinction in adversive conditioning

Abstract

One hundred and ninety-two subjects were given Pavlovian fear conditioning with several CS-UCS combinations to investigate the control and motivational properties of compound stimuli in the blocking phenomenon. The study consisted of two distinct experiments, each utilizing a transfer test design. In the first experiment, 40 rats were assigned to four groups differing in the CS-UCS combination of Pavlovian conditioning. In the subsequent transfer test the specific CSs were interposed on an operant bar press task. Analysis of the results indicated the presence of blocking both as an acquisition and extinction phenomenon. In the second experiment 152 rats were assigned to four groups similar to those of experiment 1, with the addition of an untrained control group. The transfer test consisted of 10 trials in a hurdle-jump apparatus. Analysis of the results indicated acquisition blocking but was equivocal for extinction blocking. The motivational nature of each of the component CSs in the experiments was discussed in relation to what is learned in Pavlovian fear conditioning and the affective valence attributable to such CSs in their effect on behavior.