Effect of retraining trials on memory consolidation in weakly reinforced learning

Day-old chicks given a single weakly reinforced (20% v/v methyl anthranilate in absolute ethanol) passive avoidance learning trial showed no evidence of long-term memory. A second learning trial given at 15 minutes after initial resulted in consolidation of the learning experience into long-term memory. The retention function resulting from two learning trials is similar to that observed with a single strongly reinforced learning trial, and consists of the stages postulated by Gibbs and Ng. With a dilution of 10% methyl anthranilate in ethanol, four training trials were needed to yield unequivocal evidence of long-term memory consolidation.