Attention shifts in a maintained discrimination.
Pigeons received lights of varying wavelengths paired with sounds of varying frequencies; pecking was reinforced only at one stimulus combination. Then either the light or the sound was held constant at its reinforced value, while the other stimulus continued to vary. Subsequent tests showed that the constant stimulus had lost much of its control over the birds' responses.
D000818:Animals; D001288:Attention; D001307:Auditory Perception; D010856:Columbidae; D004192:Discrimination, Psychological; D012054:Reinforcement, Psychology; D014796:Visual Perception