Conditioning of the nictitating membrane of the rabbit as a function of CS-US interval.

Abstract
An investigation was conducted to determine the effect of CS-US intervals of 250, 500, 1,000, 2,000, and 4,000 msec. on the frequency and latency of the nictitating membrane response of the albino rabbit. It was found that (a) conditioning of the nictitating membrane occurred at all interstimulus intervals: (b) rates of conditioning were inverse functions of CS-US interval; (c) the mean latency of CRs for all groups decreased over acquisition trials, and all groups differed from each other in mean CR latency during acquisition, extinction, and spontaneous recovery. The relevance of these findings to the stimulus trace and 2-factor hypotheses of interstimulus-interval effects was discussed.