CUE COMPETITION IN CAUSALITY JUDGMENTS - THE ROLE OF NONPRESENTATION OF COMPOUND STIMULUS ELEMENTS

College students rated the causal efficacy of Elements X, A, and B of food compounds AX and BX in producing the allergic reaction of a hypot hetical patient. The results of a 16-day allergy test were presented t o subjects in a serial, trial-by-trial manner. The response format use d was a running estimate, in which subjects were asked to rate all of the three foods after each of the 16 trials. Ratings of distinctive El ements A and B diverged and ratings of common Element X decreased as t he difference in the correlation of AX and BX with the occurrence and nonoccurrence of the allergic reaction increased. These human causal j udgments closely correspond with stimulus selection effects observed i n the conditioned responses of animals in associative learning studies . The experiment also directly demonstrated the fact that significant changes in the causal ratings of a stimulus occur on trials in which t he cue is not presented. Associative theories such as that of Rescorla and Wagner (1972) predict changes in associative strength only for th ose stimulus elements that are presented on a particular trial. A modi fication of the Rescorla-Wagner model is described that correctly pred icts immediate changes in the associative strengths of all relevant cu es on each trial-whether presented or not. (C) 1994 Academic Press, In c.