Examination of a backchaining/counterconditioning process during the extinction of conditioned fear.
Two experiments using rat subjects are reported which attempt to delineate the theoretical mechanisms involved in exposure/extinction procedures that are used to eliminate conditioned fear. In Experiment 1, a within-subjects design was employed to study the temporal course of the extinction process by examining the relationship among three separate measures of classically conditioned fear--suppression of an ongoing, operant behavior during the nonreinforced fear-eliciting CS presentation, the time to the first response during this CS presentation, and the time to recover responding following termination of the CS. The results indicated a temporal relationship among these measures, both within and across nonreinforced CS trials, which were considered to reflect a backchaining of a fear-antagonistic response during extinction, and provided an empirical demonstration of an extinction process consistent with Denny's (Behaviour Therapy and Experimental Psychiatry, 7, 315-321, 1976) elicitation/backchaining explanation of extinction. Experiment 2 attempted to manipulate the course of extinction and the temporal relationship among these three fear measures through the paired presentations of the fear CS with a palatable substance (maltose). This procedure produced greater extinction apparently by facilitating the backchaining process. These results are discussed with implications for exposure-based therapies.
Callen
E J
EJ
University of South Carolina, Aiken 29801.
Boyd
T L
TL
D001143:Arousal; D003214:Conditioning, Classical; D003887:Desensitization, Psychologic; D005108:Extinction, Psychological; D005239:Fear; D006801:Humans; D007171:Implosive Therapy; D011930:Reaction Time