Visual alternation by pigeons: Learning to select or learning to avoid

In the visual alternation task, pigeons learn to alternate between two stimuli (e.g., red and green) that vary randomly in location from trial to trial. The task is inherently difficult because animals tend to return to a stimulus to which they have just received reinforcement for responding. Williams (1971, Journal of the Experimental Analysis of Behavior, 15, 129-140) suggested that pigeons learn this task by learning to avoid the stimulus most recently chosen. The present experiment tested this hypothesis by involving three groups. The Standard Group replicated Williams' design. For the New Correct Group, following a correct (reinforced) response, on the next trial, the color of the new correct stimulus changed. For example, if it had been green, it changed to either blue or yellow, but the color of the new incorrect stimulus (the one that was just correct) remained the same (i.e., red). For the New Incorrect Group, following a correct response, on the next trial, the color of the new incorrect stimulus changed. For example, if it had been red, it changed to blue or yellow, but the color of the new correct stimulus remained (i.e., green). The Standard Group replicated Williams's finding that pigeons can learn the alternation task. Consistent with Williams's hypothesis, pigeons in the New Correct Group showed evidence of learning the alternation task, whereas pigeons in the New Incorrect Group showed little evidence of learning. Acquisition of the visual alternation task suggests that pigeons are cognitively flexible enough to overcome their natural tendency to repeat their most recently reinforced response to a stimulus.