Classical and instrumental eyelid conditioning.

Publisher Website
Google Scholar
Abstract
These experiments compared the effectiveness of classical and instrumental procedures for conditioning the eyeblink response of human subjects (Ss). In Expt. I, 36 Ss were conditioned by these 2 procedures with 500-msec, 800-msec, and 1500-msec. interstimulus intervals. Results showed (a) poorer conditioning under the instrumental condition, (b) the usual decrease in amount of conditioning with increasing interstimulus intervals, and (c) a tendency toward cyclical alternations of runs of CR''s and failures to respond in the instrumental condition only. In Expt. n, 24 Ss were used with half of them beginning on the instrumental condition, half on the classical condition. Midway in conditioning, half of each group was switched to the other condition. Results show a large increase in performance when the instrumental group is changed to the classical condition and a smaller reduction in performance when the classical group is changed to the instrumental condition. Again, there is evidence for cyclical alternations in the performance of the instrumental groups. In Expt. III, 12 Ss were conditioned with 2 different partial reinforcement schedules where the air puff was otherwise unavoidable. One of these schedules attempted to omit air puffs, the other attempted to introduce air puffs, where the previous instrumental groups had avoided them. Both conditioning and extinction were superior under the latter schedule. In Expt. IV, 21 Ss were conditioned under the classical procedure. In one group the CS and UCS were presented together on every trial. In 2 other groups, the CS was omitted on Trials 21-30 and 21-40, and the UCS was presented alone 10 or 20 times in an effort to manipulate S''s motivation without changing the amount of conditioning. Results of this experiment demonstrated that the omission of the CS did not interfere with the progress of conditioning. Data from 2 additional groups show that these effects depend upon the presentation of the UCS and not upon sensitization of a UCR to light.