Mechanisms of feature-positive and feature-negative discrimination learning in an appetitive conditioning paradigm.

Abstract

ost experiments on occasion setting involve some form of either M a feature-positive (FP) or feature-negative (FN) discrimination. In such discriminations, the presence of one stimulus (the feature stimulus) marks trials on which another stimulus (the target stimulus) is either paired with an unconditioned stimulus (US) or not. Not surprisingly, the feature comes to influence performance to the target. Although these discriminations seem straightforward, the psychological mechanisms that control them can be multiple and complex. This chapter describes some recent research that explored the mechanisms behind the two discriminations as they are represented in a commonly used conditioning paradigm in which food is the US and the rat’s investigation of the food cup provides the measure of conditioned responding (e.g., Brooks & Bouton, 1993, 1994; Bouton & Ricker, 1994; Delamater, 1995; Farwell & Ayres, 1979; Hall & Channell, 1985; Kaye M Pearce &Wilson, 1991). The FP and FN procedures are operationally symmetrical, and it is