Massed trial Overtraining Effects on Extinction and Reversal Performance in Turtles (Geoclemys reevesii)

Two experiments with turtles (Geoclemys reevesii) examined the overtraining extinction effect (OEE) and the overtraining reversal effect (ORE), under massed training conditions. In Experiment 1, three groups of turtles received 7, 14, or 21 sessions of training in a runway situation for food reinforcement, followed by 15 sessions of extinction. Extinction was faster, the greater the number of acquisition sessions. In Experiment 2, the two groups of turtles learned a spatial discrimination for food reinforcement either to a criterion (19 of 20 correct responses), or to that criterion plus 100 additional trials of overtraining. When the validity of the positions was reversed, learning was faster for the overtrained group than for the group trained to a criterion. This evidence of the OEE and the ORE is the first yet reported for a reptile. The results are discussed in the framework of comparative research on rewardschedule effects.