Within-day serial reversal of a position discrimination by pigeons

Naive (N = 3) and experienced (N = 3) pigeons performed 3 reversals of a simultaneous position discrimination to the same criterion each day. In terms of trials to criterion, or number of correct choices preceding the criterion run, daily first reversals (R1s) were, for both groups, more difficult than either second (R2s) or third reversals (R3s), which did not differ on these measures. The results are interpreted as giving good support to the hypothesis that little or no inhibition is generated in R1s, whereas inhibition does occur in R2s and R3s. An explanation of the relative lack of inhibition in R1s, which relies on concepts drawn from frustration theory, is proposed.