The effect of home cage environmental stimuli on learning and the effects on retention of the presence or absence of these familiar contextual training stimuli during the retention test (Experiment 1) or during the retention interval (Experiment 2) were examined using 10-day-old rats, a multidirectional active avoidance task, and a 30-min retention interval. Home cage environmental stimuli were found to improve learning. A change in stimuli immediately after training, during the 30-min retention interval, was found to have a greater impact on retention performance than stimulus change introduced at the time of the retention test. The implications of these findings are discussed in relation to ontogenetic differences in retention performance and theories of forgetting.
While previsual rats as young as 10 days of age have little difficulty acquiring an active avoidance response (AR) (Misanin, Chubb, Quinn, & Schweikert, 1974; Misanin, Turns, & Hinderliter, 1985), they do have difficulty retaining the response over even very short retention intervals. Misanin et al. (1985) found retention deficits as soon as 5 min after training and retention loss seemed complete 30 min after training. That retention loss in infant rats over intervals of 24 hr or less is due to memory for the AR being inaccessible rather than unavailable is indicated in the work of Spear and Smith (1978). These investigators found 24-hr retention of an active AR in 9-and 12-day-old rats when their memories were reactivated during the retention interval.
Since infant animals are typically returned to their home cage during the retention interval, Misanin, Turns, Lariviere, and Hinderliter (1985) examined the effect of this Reprint requests should be sent to Dr.