Assessing the contributions of S-O and R-O associations to differential-outcome matching through outcome reversals

Pigeons were trained on symbolic matching with 2 samples, 2 pairs of comparisons, and different outcomes for the correct responses within each comparison pair. For one group, the 2 samples were also associated with different outcomes, whereas for another group, they were not. When the response-outcome (R-O) relations for one pair were subsequently reversed, the group trained with differential sample-outcome (S-O) associations was significantly disrupted in its performance on both reversed- and nonreversed-outcome trials. By contrast, the group trained with just differential R-O associations was disrupted only on reversed-outcome trials. These results were replicated when the outcomes on the initially nonreversed trials were then reversed. The findings indicate that differential S-O associations, when present, have a stronger influence on matching performances than differential R-O associations. They are also consistent with hierarchical and configural models of discriminative control.