Comparison of visual and olfactory reversal learning in pigeons

Abstract

Pigeons trained to discriminate between either two different odors or two different colored lights acquired their discriminations at the same rate. When the discrimination problems were reversed within a modality, however, the birds using visual cues acquired new discriminations more rapidly than in original learning (positive transfer), whereas the birds using olfactory cues acquired the discrimination reversal less rapidly. On subsequent reversals, pigeons in the visual task condition developed a successive discrimination reversal set with repeated reversals of the stimuli, while those in the olfactory condition did not. In a second experiment designed to assess the acquisition of redundant cues, birds received additional training with visual and olfactory cues in compound as discriminative stimuli, and were then tested with only visual or olfactory cues. Birds previously trained with odor attended to visual cues in the compound, whereas birds previously trained to discriminate between lights did not attend to odor cues until they were presented alone. These results demonstrate that the selection of stimuli may play a crucial role in the performance of successive discrimination reversals and suggest that, in contrast to rats, birds selectively attend to visual over olfactory cues in discrimination learning.