Concept Learning in the Pigeon: Transfer to New Matching and Nonmatching Stimuli

Pigeons were trained to respond to matching and nonmatching stimuli--to peck a response key if the two halves matched (red/red and green/green) and not peck if the two halves were different (red/green and green/red), or vice versa and were then transferred to new matching and nonmatching stimuli (yellow/yellow, blue/blue, yellow/blue, and blue/yellow, in Experiment I; bright/bright, dim/dim, bright/dim, and dim/bright, in Experiment II). In both experiments, transfer to new colors or brightnesses was better for birds maintained on the same task as in training (i.e., a task permitting use of the same abstract concept, 'matching' or 'nonmatching,' as in training) than for birds shifted to the other task. The results indicate that pigeons can lear abstract concepts with a free-operant go/no-go procedure.