The effects of schedules of reinforcement and gradual or abrupt increases in reward magnitude on resistance to extinction

Abstract

During an initial phase of acquisition training, rats were given 41 trials (1 trial/day). The continuous-gradual group received one 45-mg food pellet on each trial during this phase, as did the continuous-abrupt group. Two partial groups, the partial-gradual and partial-abrupt groups, were maintained on a 50% partial reinforcement schedule during this initial phase, with one food pellet as reward on reinforcement trials. In a subsequent 11-day acquisition phase, the continuous-abrupt and partial-abrupt groups were shifted immediately to a 12-pellet reward magnitude administered according to the reinforcement schedule received during Phase 1. The continuous-gradual and partial-gradual groups also continued on their respective reinforcement schedules but experienced gradual increases in reward magnitude up to 12 pellets. Finally, all subjects were given 20 trials of extinction training. The extinction results showed that with partial reinforcement training, gradual increases in magnitude of reward produced greater resistance to extinction than did abrupt increases in reward amount. The theoretical significance of these data was discussed.