Contingency and contiguity on the responding by rats exposed to variable interval, variable ratio and variable time schedules of reinforcement

Abstract

In this study, we examined the effects of introducing a delay of reinforcement on the rate and distribution of lever-pressing of eight rats under interval, ratio, and time reinforcement schedules (VI, VR, and VT). Following baseline conditions under immediate reinforcement, an unsignaled and nonresetting 5-s delay of reinforcement was introduced upon each of these schedules. Results showed that the delay was accompanied by a decrease in the rate of responses for all subjects, for all three schedules of reinforcement, most noticeable for VT, followed by the VI and then the VR schedules. A molecular analysis of the data revealed that, under VI, but not VR, the subjects' actual delay approximated the programmed value of 5 seconds. In general, results demonstrate that the effects of introducing a delay of reinforcement depend on the current reinforcement schedule. In the present study, in particular, response rate and response distribution under VI and VR, were followed by different effects of the delay when controlling respectively for time and ratio of responses. Keywords: contingency; contiguity; delay of reinforcement; schedules of reinforcement; rats.

Keywords

• contingência
• contigüidade
• atraso do reforço
• esquemas de reforçamento
• ratos