Acquired distinctiveness is controlled by stimulus relevance not correlation with reward

In 2 experiments, the relationship between the role of a stimulus in signaling trial outcome and the attention paid to it was investigated. In Experiment 1, an intradimensional-extradimensional shift effect was shown in pigeons using autoshaping. In Experiment 2, pigeons were trained with a biconditional discrimination, using stimulus compounds varying on 3 dimensions (color, orientation, and position), 2 of which were relevant to the solution of the discrimination, and 1 of which was irrelevant. Acquisition of a subsequent biconditional discrimination was more rapid if the same stimulus dimensions were relevant to the solution of both discriminations than if a previously irrelevant discrimination became relevant. These results indicate that the amount of attention paid to a stimulus is determined by its relevance to the solution of a discrimination, and not by its correlation with reward.