Inhibitory associations between neutral stimuli: A comparative approach

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