Periodic response-reinforcer contiguity: Temporal control but not as we know it!

Two experiments using rats show the effects of introducing response-reinforcer contiguity on a modified recycling conjunctive fixed-time 30 s fixed-ratio 1 schedule of food reinforcement. In Experiment 1, the frequency of programmed contiguity was varied across conditions. The general finding was an increase in overall rate of responding for all rats when the incidence of obtained contiguity was relatively high. This increase in responding was accompanied by unusual response patterns for some rats. These patterns persisted when the rats were subsequently exposed to a fixed-interval schedule. Other rats produced fixed-interval-like performance when the incidence of obtained contiguity increased. Similar findings were observed in Experiment 2 where a more direct comparison was made between the modified recycling conjunctive schedule and the fixed-interval schedule. Results in general emphasize the importance of the modified recycling conjunctive schedule as a tool for exploring behavioral adaptation to periodic reinforcement. The history effects reported in both experiments are discussed with reference to the notion of schedule-induced behavior and temporal control.