A COMPARISON OF VISUAL AND OLFACTORY STIMULI IN REVERSAL LEARNING WITH PIGEONS

Pigeons trained to discriminate either two odors or two lights acquired their discriminations at the same rate. When the discrimination problems were reversed within a modality, however, the birds using visual cues acquired the discriminations more rapidly than in original learning (positive transfer), while the birds using olfactory cues acquired their 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, odor-trained birds used visual cues to make discriminations when both odors and lights could serve as discriminative stimuli. Birds originally trained to discriminate lights did not use odor cues when both lights and odors were available as discriminative stimuli. These results are discussed within the framework of traditional learning theory accounts and suggest that biological factors exert control over the ability of organisms to make various stimulus-reinforcer associations.