Effects of age on some behavioral characteristics of novel auditory stimuli in the rat.

Low intensity novel auditory stimuli have two behavioral characteristics. First, such stimuli elicit exploratory behavior directed at the sound source. Second, novel stimuli gain control of responding in a discriminative task more rapidly than familiar stimuli. Experiments were carried out to investigate these two characteristics of novel stimuli. In the first experiment 3, 12 and 30 month old rats were given three sessions, 24 hours apart, of exposure to an initially novel low intensity series of noise pulses; the number of exploratory responses of the sounding speaker per session was counted. In the second experiment, 12 and 30 month old rats were trained in a sound location discrimination in which the stimuli were made familiar prior to discrimination training. Age had no effect on the amount, habituation and retention of habituation of exploration of the sounding speaker. In the second experiment, the 12 month and 30 month old animals acquired the discrimination at the same rate; again no age effect was found.