Pavlovian aversive to instrumental appetitive transfer: Evidence for across-reinforcement blocking effects

Abstract

Rats received Pavlovian aversive (shock) conditioning in which white noise was established for different groups as a es+, eso, or es-. Then, in an appetitive T-maze discrimination, the ess were presented contingent upon adesignated correct response for which food reinforcement was factorially varied at 0, 1, 2, or 4 pellets. Although the es+ suppressed and the es-facilitated speed of running in the correct arm at the start of discrimination training, these effects extinguished rapidly and did not interact with reward magnitude. Furthermore, choice learning was faciltated by the es+ and retarded by the es-, with these effects being comparable for the 1-to 4-pellet reinforcement conditions, but ab sent for the O-pellet condition. These findings are difficult to reconcile with a transfer interpretation positing a general signaling property of the es and are better interpreted as across-reinforcement blocking effects: By predicting a preferred outcome (safetyl comparable to the preferred outcome of food reinforcement, the es-blocks (retardsl the association of reinforcement and the SD; conversely, by predicting a nonpreferred Ishock] outcome discrepant from the preferred food outcome, the CS+ "counterblocks" (enhancesl the association of reinforcement and the SD.

Stimulus Control and Associative Learning

“…Fowler, Goodman, and Zanich (1977) established white noise as a conditioned inhibitor with respect to shock in a Pavlovian discrimination procedure, and then presented the noise contingent on the correct response in a T maze. Correct choices were also followed by food, with the noise intervening between the choice point and entry into the goal box.…”

Transfer from Pavlovian appetitive to instrumental appetitive conditioning: Signaling versus discrepancy interpretations.

“…More recent findings (Fowler, Goodman, & DeVito, in press;Fowler, Goodman, & Zanich, 1977) have contested this "signaling" interpretation and have suggested an alternative interpretation based on Rescorla and Wagner's (1972) reinforcement limit or "discrepancy" theory of blocking and related phenomena (see also Kamin, 1968Kamin, , 1969. According to this new interpretation, an AvCS-will block, that is, retard, conditioning to the discriminative stimulus (S D ) with which it is associated in Ap discrimination training because the occurrence of food reinforcement produces little surprise or a relatively small discrepancy as compared with the expectation of no shock generated by the AvCS-; in short, the "good" outcome of safety predicted by the AvCS-is comparable to the "good" outcome of food reinforcement, and thus the AvCS-limits the effectiveness of the food reinforcer.…”