Stimulus change in light-contingent bar pressing.

Abstract

An attempt was made to separate the effects of initial intensity, consequent intensity, and amount of change on light-contingent bar pressing (LCBP) in order to test the stimulus-change hypothesis that increments and decrements in illumination will be equally reinforcing and that rate will be an increasing function of the amount of change. Each of 12 combinations of change between 4 intensities were tested with 5 male albino rats which were given 5 days each of operant and LCBP conditions and 2 days of extinction. The interaction between initial and consequent level was consistent with the stimulus-change hypothesis; no differences in response duration were observed between operant and LCBP testing, and the reinforcer was affective after 3 responses.