AUDITORY DIFFERENTIAL CONDITIONING OF RABBIT NICTITATING MEMBRANE RESPONSE .2. EFFECTS OF INTERSTIMULUS INTERVAL AND CUE SIMILARITY

In Experiment 1 each of48Ss was given 3 days of conditioning in a 3 by 2 factorial design combining interstimulus intervals (ISIs) of 250, 500, and 1000 msec with frequency separations (Δf) between the reinforced (CS+) and nonreinforced (CS-) conditioned stimulus of 200 and 1400 Hz. The results revealed poor differentiation with Δf=200Hz and uniformly good differentiation with Δf= 1400 Hz. This finding suggests that the effect of ISI upon differentiation is minor. The purpose of Experiment 2 was to determine whether the inhibitory influence of nonreinforcement was greater in a partial reinforcement paradigm, where the same CS is as often reinforced as nonreinforced, than in a differential conditioning paradigm with discriminably different CSs. A comparison of rate of responding to CS+ between a group of eight Ss given 50% partial reinforcement with two groups of eight Ss receiving differential conditioning at two levels of Δf (600 or 1200 Hz) indicated that the partial reinforcement Ss did not differ significantly from the two differential groups. © 1969, Psychonomic Journals, Inc.. All rights reserved.