Reconsidering conditioned inhibition

Conditioned inhibition is a fundamental component of contemporary learning theory. Our selective review of the literature defines the term conditioned inhibition on three levels-operational, behavioral, and theoretical-in ord er to evaluate the utility of the construct. Although consensus definitions are found at the operational and behavioral levels, the principal disagree ment exists, not surprisingly, at the theoretical level. The comparator hyp othesis suggests that the concept of inhibition is superfluous because beha vior that is indicative of inhibition can be explained more parsimoniously by noninhibitory theoretical mechanisms. Furthermore, the findings that inh ibition is less pervasive than and not always mutually exclusive with excit ation suggest that the original view of inhibition as the opposite of condi tioned excitation is no longer viable. However, rejection of the original c onception of inhibition does not invalidate the theoretical utility of inhi bition as a construct in other paradigms (e.g., occasion setting). (C) 1999 Academic Press.