Counterconditioning of an overshadowed cue attenuates overshadowing

In 3 Pavlovian conditioned lick-suppression experiments, rats received over shadowing treatment with a footshock unconditioned stimulus such that Condi tioned Stimulus (CS) A overshadowed CS X. Subjects that subsequently receiv ed CS X paired with an established signal far saccharin (CS B) exhibited le ss overshadowing of the X-footshock association than subjects that did not receive the X-B pairings (Experiment I). Experiment 2 replicated this effec t and controlled for some additional alternative accounts of the phenomenon . In Experiment 3, this recovery from overshadowing produced by countercond itioning CS X was attenuated if CS B was massively extinguished prior to co unterconditioning. These results are more compatible with models of cue com petition that emphasize differences in the expression of associations than those that emphasize differences in associative acquisition.