Cross-Modal Stimulus Class Formation in Rats

Abstract

This experiment examined the whole-partial effect of overtraining in concurrent discriminations using two different sensory modality tasks (tactual and visual task) and assessed the effect against single discrimination training in rats. Overtraining facilitated reversals in both Group W, in which rats were given concurrent training on two tasks in the original learning before both tasks were reversed, and Group S, in which rats were trained only on the tactual task before it was reversed. Overtraining retarded reversal in Group P, in which rats were given the same training as in Group W in original learning, but only the tactual task was reversed. After overtraining, Groups Wand S reversed more rapidly than Group P. After criterion training, Group P reversed more rapidly than Group W, which reversed more rapidly than Group S. These findings indicate that rats form stimulus classes (i.e., cross-modal stimulus classes) between the discriminative stimuli of two different sensory modalities with the same response assignment during overtraining in two concurrent discriminations as well as between the discriminative stimuli of the same sensory modality.