Acquisition, extinction, and retention of an avoidance response in rats as a function of age.

Abstract

In Experiment 1, rats 25, 50, and 100 days old were conditioned in a runway to avoid shock at the sound of a buzzer and then extinguished to a criterion. Of 2 groups at each age level, 1 was randomly selected, trained, and extinguished, and 1 was matched for performance during acquisition and then extinguished in order to study resistance to extinction with original learning held constant. There were no significant differences in acquisition or extinction in matched or unmatched groups. The 2nd experiment measured retention of an avoidance response 1, 25, and 50 days following conditioning at 25, 50, and 100 days. The number of avoidance responses in a 30-trial reconditioning test indicated that retention was significantly lower in the 25-day-old group than in the 2 older groups. (PsycINFO Database Record (c) 2006 APA, all rights reserved)