Retention of Differential Autonomic Conditioning and Memory for Conditional Stimulus Relationships

Corollary to the hypothesis that awareness of the conditional stimulus relationships is necessary for the acquisition of differential conditioning, it was predicted that memory for the conditional stimulus relationships (i.e., awareness at retention testing) would be necessary for the retention of differential autonomic conditioning. Groups of 20 subjects each were tested for retention of differential skin conductance and vasomotor conditioning, differential expectancies of the unconditional stimulus, and memory for the CS-US relationships either 1 day or 28 days after initial acquisition. A continuous measure of expectancy of the unconditional stimulus was obtained during initial acquisition and retention testing. Retention testing consisted of a series of unreinforced presentations of the conditional stimuli and a reacquisition series. The 28-day interval resulted in more forgetting of the conditional stimulus relationships and greater retention loss of differential autonomic conditioning and differential US expectancies than did the 1-day interval. Within the group tested after 28 days, retention loss was related to the subjects' post-experimental reports of whether or not they remembered the CS-US relationships. Subjects reporting having forgotten showed complete retention loss of differential autonomic conditioning and differential US expectancies while subjects reporting having remembered showed good retention, similar to that shown after the 1-day retention interval. The hypothesis that memory for the conditional stimulus relationships is necessary for retention of autonomic conditioning was supported. It was also found that long-term memory for the conditional stimulus relationships was related to greater autonomic responsivity during initial acquisition.