Differential outcomes and many-to-one matching: Effects of correlation with correct choice

Pigeons trained on many-to-one matching-to-sample with different probabilities of reinforcement for correct choice acquired the task more rapidly and showed better working memory performance when those different probabilities were correlated with the correct comparisons than when they were uncorrelated with them. Furthermore, this advantage was maintained when all correct choices were subsequently reinforced at the same probability, even though the change to nondifferential outcomes produced a drop in accuracy in the (formerly) correlated group. When birds were later shifted from correlated to uncorrelated outcomes or vice versa, the original between-group differences were reversed or eliminated. These data suggest that differential outcomes will potentiate matching performance if they generate an expectancy cue that is also predictive of correct choice. In addition, different outcomes may enhance common coding of the samples in many-to-one matching to the extent that they too are correlated with the correct comparison alternatives.