Partial reinforcement effect: The expectancy of reward on nonreward trials

Abstract

In order to determine the importance of the developmen t of expectancy of reward prior to partial reward trials; rats were given 20 continuously reinforced trials prior to 20 partially reinforced trials (CRF-PRF) and compared to Ss given only 20 partially reinforced trials (PRF). Control groups received 20 or 40 continuously reinforced trials to determine the effect of differing numbers of acquisition trials. Results showed that terminal acquisition differences were minimal in the run segment of the alley and that Group CRF-PRF was more resistant to extinction than Group PRF, and both were more resistant to extinction than the CRF-20 and CRF-40 groups, which did not differ from each other. These results were interpreted as supporting the notion that the expectancy of reward on nomeward trials during partial reinforcement acquisition is a determiner of the magnitude of the partial reinforcement extinction effect.The frustration explanation of the partial reinforcement extinction effect (PREE) requires that the expectancy of reward (rr) be developed first so that later primary frustration (R F ) will occur on nonreward trials and subsequently the anticipation of frustration (rf) and its stimulus consequence (Sf) will be conditioned to approach (Amsel, 1967). If Sf has not been conditioned to approach at the start of extinction, then the PREE will not occur.Capaldi's sequential hypothesis requires only that nonreinforced trials be followed by a reinforced running trial in order to produce a PREE (Capaldi, 1966(Capaldi, , 1967. No mention is made of the necessity of establishing an expectancy of reward prior to partial reinforcement in order for PREE to occur, although recently Waters (1970) andCapaldi, Berg, andSparling (1971) have considered the possible importance of some form of frustration during PRF acquisition in governing resistance to extinction. Sutherland and Mackintosh (1971) claim that continuous reinforcement (establishing rr) prior to partial reinforcement training will reduce the PREE relative to a condition where only partial reinforcement training is given. This prediction is based on the notion that a determiner of the PREE is the number of stimulus analyzers which are switched in and that continuous reinforcement will strengthen only one analyzer and produce less resistance to extinction because only responses to this analyzer need to be weakened for

Persistence: The role of partial reinforcement in psychotherapy.

“…Most dramatic are results from the Mellgren et al (1978) experiments, which provide clear evidence that the effect of increasing the number of C trials (0, 48, or 96) before a constant number of P trials (32) is to increase persistence during extinction. These results, which are somewhat consistent with earlier findings (Mellgren et al, 1973;Theios & McGinnis, 1967;Traupmann et al, 1973), are more difficult to interpret theoretically. Frustration theory, as previously described, would seem to be able to make the most sense out of the Mellgren et al data.…”