Context specificity of operant discrimination performance in pigeons.

In an experiment designed to investigate odors as potential retrieval cues in pigeons' memory (i.e., as conditional stimuli), 8 pigeons first learned to peck a red keylight (S+, reinforced) and not a blue one (S-, extinguished) in the presence of either a eucalyptus oil or isoamyl acetate odor. They were repeatedly switched between two chambers with the same odor to habituate any reaction to the switching that would be required for eventual testing for conditional control by the odors. Next, the birds learned the reversal (blue S+, red S-) in the presence of the alternative odor in one of these chambers. When the birds were then switched to the alternative chamber for additional training, although the odor was still appropriate to the reversal problem, behavior appropriate to the original training condition recurred. Testing indicated that reversal performance was specific to the one chamber in which it had been trained.