METHOD AND THEORY IN STUDY OF AVOIDANCE

Devised 2-factor theories of avoidance to explain responding in avoidance procedures that closely resemble the Pavlovian paradigm in superficial features, although differing in the fundamental contingency of reinforcement. Both typically involve an arbitrary CS and a trial-by-trial sequence of pairings between the CS and UCS. According to 2-factor theory, the instrumental reinforcement of avoidance is based on the Pavlovian reinforcement of a drive state in the presence of the CS. It has been shown that the presence of the CS is not necessary for the occurrence of avoidance responding. A procedure in which the sole effect of the avoidance response was a reduction in the average frequency of occurrence of an aversive electric shock proved to fully adequate to maintain lever pressing in rats, thereby suggesting that not all avoidance requires 2 factors. Further experiments with various new procedures suggested that the CS may function as a discriminative stimulus for the avoidance response, rather than as a stimulus whose removal is inherently reinforcing, as 2-factor theory requires. (56 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.