Cognitive factors and CS-UCS interval effects in the differential conditioning and extinction of skin conductance responses.

Mandel and Bridger (1967) found resistance to extinction of differentially conditioned skin conductance responses by subjects, who, according to a post-conditioning questionnaire, believed pre-extinction instructions that the shock-UCS would no longer be administered. The present study was intended to: (1) determine whether or not an extraordinarily noxious shock-UCS is required to produce such results; (2) eliminate possible retrospective falsification effects associated with the use of a post-conditioning questionnaire by monitoring subjects' UCS expectancies continuously throughout extinction as well as acquisition trials; (3) attempt to confirm that resistance to extinction is stronger with a 0.5 sec CS-UCS interval than with an 8 sec interval; and (4) test several predictions regarding UCS expectancies during the intertrial intervals of acquisition. After receiving 16 instructed acquisition trials, two groups (N = 20 in each) exposed to either a 0.5 sec or 8 sec CS-UCS interval were fully instructed regarding discontinuation of the UCS during the pending 20 extinction trials. Reliable differential conditioning was obtained during the first extinction trial block for subjects who, according to the expectancy monitoring measure as well as a post-conditioning questionnaire, did not expect UCS administration. The extent of resistance to extinction did not differ between the two groups. Consistent with predictions from a cognitive viewpoint, the expectancy monitoring data of the two groups differed significantly during the intertrial intervals of acquisition.