REINFORCEMENT OMISSION ON FIXED-INTERVAL SCHEDULES

Experiments with pigeons and rats showed that: (1) When a brief blackout was presented in lieu of reinforcement at the end of 25% of intervals on a fixed‐interval 2‐min schedule, response rate was reliably and persistently higher during the following 2‐min intervals (omission effect). This effect was largely due to a decrease in time to first response after reinforcement omission. (2) When blackout duration was varied, within sessions, over the range 2 to 32 sec, time to first response was inversely related to the duration of the preceding blackout, for pigeons, and for rats during the first few sessions after the transition from FI 2‐min to FI 2‐min with reinforcement omission. Post‐blackout pause was independent of blackout duration for rats at asymptote. These results were interpreted in terms of differential depressive effects of reinforcement and blackout on subsequent responding. 1969 Society for the Experimental Analysis of Behavior