Effect of response interference on diminution of electrodermal unconditioned response.

The purpose of this experiment was to study whether the phenomenon called - conditioned diminution of the unconditioned response (UR)- is produced by t he physiological mechanism of response interference, or fusion, between the conditioned response (CR) and the UR, as suggested by the response interfe rence and inhibition of delay hypotheses. Sixty volunteer subjects received discrimination training in which a CS was reinforced (CS+/US) and a second CS was not reinforced (CS-). The interval between the CS and unconditioned stimulus (US; aversive white-noise) was 8 seconds. Only the results of sub jects exhibiting discriminative control were analyzed. The results show tha t neither the amplitude, nor the latency of the preceding CR affect the amp litude of the UR. Because these results cannot be explained by the response interference or inhibition of delay hypotheses, an alternative explanation is offered, suggesting the presence of an associative basis of the phenome non.