A model for Pavlovian learning: Variations in the effectiveness of conditioned but not of unconditioned stimuli

Abstract

Part 1 of this discussion summarizes several formal models of exicitatory classical conditioning. It is suggested that a central problem for all of them is the explanation of cases in which learning does not occur in spite of the fact that the CS is a signal for the reinforcer. A new model is proposed that deals with this problem by specifying that certain procedures cause a CS to lose effectiveness; in particular, it is argued that a CS will lose associability when its consequences are accurately predicted. In contrast to other current models, the effectiveness of the reinforcer remains constant throughout conditioning. Part 2 presents a reformulation of the nature of the learning produced by inhibitory-conditioning procedures and a discussion of the way in which such learning can be accommodated within the model outlined for excitatory learning. (47 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1980 American Psychological Association.