Response-independent outcome presentations weaken the instrumental response-outcome association.

October 2022

Abstract

The present article explored the fate of previously formed response-outcome associations when the relation between R and O was disrupted by arranging for O to occur independently of R. In each of three experiments response independent outcome delivery selectively reduced the R earning that O. Nevertheless, in Experiments 1 and 2, the R continued to show sensitivity to outcome devaluation, suggesting that the strength of the R-O association was undiminished by this treatment. These experiments used a two-lever, two-outcome design introducing the possibility that devaluation reflected the influence of specific Pavlovian lever-outcome associations. In an attempt to nullify the influence of these incidental Pavlovian cues Experiment 3 used a single bidirectional vertical lever that rats could press left or right for different outcomes. Again, response-independent outcome presentations selectively depressed the performance of the R that delivered the response-independent O. However, in this situation, the response independent O also reduced the sensitivity of R to outcome devaluation; whereas the nondegraded R was sensitive to devaluation, the degraded R was not. We conclude that selective degradation of the instrumental contingency can weaken a specific R-O association while leaving other R-O associations intact. Furthermore, the use of a bidirectional vertical lever in Experiment 3 revealed that unidirectional and spatially separated instrumental manipulanda, such as levers or chains, may produce Pavlovian cues capable of forming incidental associations with the instrumental outcome that can obscure the relative influence of R-O associations after various manipulations.