Long-term retention of Pavlovian serial feature-positive and feature-negative discriminations

Fifteen pigeons were concurrently trained with Pavlovian serial feature-positive (F-P) and feature-negative (F-N) discrimination tasks (A-, X→A+; B+, Y→B-), and retention of these discriminations was tested after a 2-week interval. The birds maintained the discriminations. After retraining of the original tasks, seven birds were tested with a one-month interval. Reliable deterioration was observed in the both discriminations due to increases in responding on the nonreinforced trials (A- for the F-P discrimination and Y→B- for the F-N discrimination). The remaining eight birds also were tested after a one-month interval, but they received 3-day retraining of the target stimuli (A- and B+) before the test. There was no loss of the discriminations in these birds, suggesting reactivation of discriminations by the target retraining.