Is stimulus competition an acquisition deficit or a performance deficit?

Abstract

Traditionally, blocking (X-outcome, followed by XY-outcome, resulting in attenuated conditioned responding to Y, relative to XY-outcome alone) has been explained in terms of the X-outcome association's preventing the acquisition of the Y-outcome association. This view is challenged by models that view stimulus competition as a deficit in the expression of the acquired Y-outcome association. Here, we provide evidence that blocking is a performance deficit in which the Y-outcome association, the to-be-blocked stimulus, can affect behavioral control by the blocking stimulus (i.e., attenuate responding to X). The results are discussed in terms of acquisition and performance models of stimulus competition. Copyright 2004 Psychonomic Society, Inc.