The effect of UCS inflation and deflation procedures on 'fear' conditioning

Davey (1992: Classical conditioning and the acquisition of human fears and phobias: a review and synthesis of the literature. Advances in Behaviour Re search and Therapy, 14, 29-66) hypothesized that subjective revaluation of an unconditioned stimulus (UCS) would determine the strength of the autonom ic conditioned response (CR) in the fear conditioning paradigm. The purpose of the present study was to examine the effect of UCS aversiveness on the CR strength in the fear conditioning paradigm. The UCS aversiveness was con trolled by the UCS intensity. that is, the UCS intensity was increased for the inflation group or decreased for the deflation group. Thirty subjects w ere randomly assigned to the inflation or the deflation group, and they par ticipated under both experimental and control conditions. All subjects went through the pretest, the acquisition of classical conditioning, the UCS in tensity operation, and the test sessions. The indices of the CR were skin c onductance responses (SCRs) and a subjective aversion to the conditioned st imulus (CS. The main results were as follows. (1) The CR strength measured by SCR was increased by the UCS inflation and decreased by the UCS deflatio n. (2) The subjective aversiveness of the CS was not sensitive to both mani pulations of UCS intensity. These results suggested that the autonomic CR s trength might be influenced by the subjective revaluation of UCS. as Davey (1992) described. The result from the test of the subjective aversiveness o f the CS, however, could not support Davey's model. The difference between expressions of the SCR and the subjective aversiveness of the CS might be c aused by different learning systems. (C) 2001 Elsevier Science Ltd. All rig hts reserved.