Abstract
Twelve- and thirty-month old Sprague Dawley rats were trained in an auditory discrimination using a discrete trial procedure with food as the reinforcer. Two thirty-month and two twelve-month animals acquired the discrimination in one trial. The asymptotic level of correct responding was lower for the old animals and this was attributed to changes in auditory threshold with age. The thirty- month animals gave more intertrial interval responses than the twelve-month animals. There was no difference in the average response latency for the two age groups.