Persistence of nonreinforced responding as a function of the direction of a prior-ordered incentive shift.

Abstract

After a pretraining period in which all Ss were trained to bar press for water, 2 groups of rats were given 4 30-sec. reinforced trials and 4 30-sec. nonreinforced trials daily for 12 days. During each reinforced trial, Ss received continuous reinforcement of a sucrose solution. The concentration of the sucrose was progressively shifted either up or down over the 4 reinforced trials. The group which received the increasing incentives bar pressed reliably less than the decreasing-incentive group during the reinforced phase, but reliably more during the nonreinforced test. Also, the interaction between the terminal reinforced trial and the 1st test trial was reliable, with the increasing group pressing less during the last reinforced trial, but more during the 1st nonreinforced trial. These results support an interpretation of extinction as due to a motivational decrement rather than the terminal level of reinforced performance, and are inconsistent with several other currently popular interpretations.

Retention of reinforcer magnitude.

“…The 5"s given high terminal sucrose concentration were more resistant to extinction than 5"s whose final sucrose concentration was low. The same phenomenon was found by Marx, Tombaugh, Cole, and Dougherty (1963) with a bar-press response.…”

Speed of nonreinforced running response following increasing and decreasing orders of sucrose concentrations.

“…It is concluded that the present results confirm the ones earlier obtained (Marx et al, 1963), thus indicating that the effect on nonreinforcement is not a function of the amount of incentive consumed and extending the generality of the effect to the runway. It should be noted that the present data do not constitute evidence for the effectiveness of the order variable per se ; since this was not separated from the terminal level of the incentive in these experiments.…”

“…The two experiments used essentially the same design as the Marx et al (1963) experiment. Experiment I utilized increasing and decreasing percentages of sucrose concentration, and Exp.…”

Effects of ordered and constant sucrose concentrations on nonreinforced performance.

“…Apparatus,-The apparatus was the same as described by Marx et al (1963). In brief, it consisted of eight operant-conditioning boxes in which each bar press (BP) mechanically operated a dipper located below the bar.…”

“…Others (Campbell, 1958;Guttman, 1953;Young & Green, 1953) indicate that some dimension of the reinforcement properties-taste, receptor sensitivity, or a motivational property, is a more important variable. Marx, Tombaugh, Cole, and Dougherty (1963) trained two groups 1 This research was supported by United States Public Health Service Grant MH00817-10 from the National Institute of Mental Health, United States Public Health Service Grant HD0089S-10 from the National Institute of Child Health and Human Development, and National Science Foundation Grant GB229 from the National Science Foundation. The authors wish to thank Judith E. Peterson for her assistance in collecting the data from Exp.…”