ABSTRACT
A cognitive theory is one which rejects certain assumptions of the theoretical tradition which has long dominated the study of animal behavior, namely, stimuli and responses (S-R) theory. If the fundamental assumption of S-R theory is a commitment to associationism, the most prominent assumption is that associations are formed only between specific classes of event, for the S-R theorist between responses and antecedent stimuli. Blocking was attenuated by a surprising change in reinforcement on compound trials but not by a change on retraining trials. The phenomenon of blocking appears to be only one example of a more general interaction between the elements of a compound conditioned stimulus. The course of conditioning to one element of a compound depends not only on the salience or correlation of that element with the reinforcer, but also on the salience and current and past correlation of the other element with that reinforcer.
