Effects of A Masking Task on Schedule Discrimination and Extinction in Humans

Abstract

Humans were exposed to a multiple fixed-interval 20- s/variable-ratio 15 schedule of lever pressing, with an anagram solution task, the “masking task, ” either concurrent with, or alternating with the operant task. In Experiment 1, subjects with the concurrent anagram task, the “masked” subjects, did not discriminate between the different components of the operant task. Subjects with the alternating anagram task, the “unmasked” subjects, did discriminate between the two components of the operant task. In Experiment 2, the operant response rates of the masked subjects did not decline during extinction of operant responding. the response rates of the unmasked subjects declined greatly during extinction. In Experiment 3, only masked subjects were run and both the operant task and the anagram task were put on extinction. Operant response rates and anagram response rates did not decline during extinction. Experiment 4 alternated masked and unmasked operant sessions in counterbalanced fashion across different subjects. Results replicated Experiments 1, 2, and 3, and some subjects developed discriminative responding during the unmasked sessions which was maintained during subsequent masked responding. The behavior of the subjects during the present experiments is likely to be controlled by: implicit task demands, explicit task demands (i.e., Instructions), attended-to reinforcement contingencies, and contingency-related subject-produced verbal rules.