Acquisition and extinction under single alternation and random partial-reinforcement conditions with a 24-hour intertrial interval.

Abstract

Rats were run 1 trial a day for 192 days on single alternations of reward and nonreward and on a random 50% pattern of reward and nonreward. No evidence for patterned running was found in the single alternation group or for the aftereffects of reward and nonreward in the random group. Large differences were found in extinction between these groups and a continuous control, both partial groups showing almost no extinction over 44 days relative to the continuous control group. The slight extinction differences between the single alternation and random groups were attributable to asymptotic acquisition performance differences. The results were discussed in relation to hypotheses that appeal to carrled-over traces of the aftereffects of reward and nonreward from one trial to the next.