Inhibitory associations between neutral stimuli: A comparative approach

In Experiments 1A, 1B, and 1C, nonhuman subjects, rats, received long alternated exposures to two compound flavors, AX and BX, that shared one flavor in common, X. Following this, conditioning of an aversion to A was sufficient to establish B as a conditioned inhibitor of the aversive unconditioned stimulus, passing both summation and retardation tests. Two additional experiments (Experiments 2 and 3) expanded the generality of these results to humans, using similar designs but an auditory discrimination learning task. A set of notes sequentially presented served as cues and fictitious composers served as outcomes. Both summation and retardation effects were found (Experiments 2 and 3, respectively). Experiment 4 then sought to clarify the mechanism underlying these effects. The results are discussed within several theoretical frameworks, most centrally the McLaren, Kaye, and Mackintosh (1989) theory of perceptual learning.