Relative Effects of Delayed Reinforcement and Partial Reinforcement on Acquisition and Extinction

Abstract

While the effects of delayed reinforcement have been studied under n wide variety of conditions, the effects of delay on acquisition and extinction relative to those of partial reinforcement, other factors constant, have not as yet been determined. In this experiment, two groups were employed. In the case of one group, immediate reinforcement was given on one trial, delayed reinforcement on the other in alternating fashion. In the case of the other group, immediate reinforcement alternated with nonreinforcement. Regarding acquisition, three specific comparisons were of primary concern to this investigation. First, it is characteristic of partial reinforcement that running speeds in the early stages of training are significantly less rapid on trials following non-reinforcement as opposed to trials following reinforcement (Bloom & Capaldi, in press; Capaldi & Senko, 1961; Tyler, Wortz, & Bitterman, 1953). The initial concern, then, was to determine if such was also characteristic of delayed as opposed to immediate rrials. Another comparison of interest involved asymptotic running speeds which have been shown to be higher under partial as opposed to consistent reinforcement (Goodrich, 1958; Weinstock, 1958). In the case where reinforcement and nonreinforcement are consistently alternated, it has been shown that later in training rat Ss run quite rapidly on the reinforced trials (Bloom & Capaldi, in press; Tyler, et al., 1953). The second concern, then, was to determine if a delay group would run as rapidly in the later stages of training as a partial group on those uials which were immediately reinforced in both groups. The final determination as regards acquisition grows out of a recent study by Wike, Kintsch, & Gutekunst (1959), who found that increased resistance (continuous reinforcement control) occurred when delayed trials preceded immediate trials but not when delayed trials followed immediate ones. Grosslight, Hall, and Murnin ( 1953 ) and Grosslight and Radlow ( 1955 ) have shown that similar variations involving nonreinforcement rather than delay support an aftereffects hypothesis (Sheffield, 1949). If the aftereffects of delayed and of immediate trials are indeed discriminably different, then, when delayed and immediate uials are given according to an alternating schedule, the rats should run relatively more rapidly on the immediate trials later in training (Bloom & Capaldi, in press; Capaldi & Senko, 1961 ) . Indeed, Wike, et aL. (1959) suggested that some of their delay Ss did manifest such pattern