Conditioned Inhibition in a Multiple Category Learning Task

Abstract

Four experiments investigated inhibition that might arise in a task in which cues are associated with more than one outcome. In each experiment, human subjects played a game called “Clues and Culprits” in which they were asked to judge the predictive strength of clues that had been associated with culprits in a series of hypothetical crimes. In a two-outcome version of the familiar conditioned inhibition paradigm (A+, AX-), one clue was paired with one culprit on its own, but it was paired with a second culprit when it was combined with a second clue (A-1, AX-2). According to the delta rule, X should acquire inhibition for the first culprit; it should also acquire more inhibition than a differential cue merely associated with a second culprit (e.g. A-1, X-2). Inhibition was found with both procedures. However, the amount of inhibition did not differ between them, suggesting that mere association with a second outcome was sufficient to inhibit performance based on the first. Other data suggested the presence of cue competition. Also, when a cue associated with one culprit was paired with a second culprit on other trials, there was little evidence of unlearning of the first association.