Discrimination acquisition and reversal in the rat as a function of number of negative stimuli.

Abstract

In two experiments on rats (ws = 28, 36), acquisition and reversal of a simple brightness discrimination were evaluated as a function of the number of negative stimuli (one, Group 2; two, Group 3; four, Group 5) paired with a single positive stimulus. In reversal learning, groups with more negative stimuli consistently were significantly superior. Experiment 1: Group 5 > Group 2, Group 3 > Group 2; Experiment 2: Group 5 > Groups 2 or 3, Group 3 > Group 2. No significant group effects in acquisition were obtained. Results are discussed in relationship to the cue function of the negative stimulus and the overlearning reversal effect.

Continuity theory revisited: A failure in a basic assumption.

“…Handler (1968), employing a transfer design, has found additional evidence for the argument that the negative stimulus is nonmonotonic. More recently, Schaeffer and Shandro (1969) have provided evidence supporting the nonmonotonicity hypothesis, using a design with multiple negative stimuli.…”