In Experiment 1, groups of rats 16, 19, 25, 32, and 90 to 120 days of age, were tested for retention of a passive avoidance response 2 min or 24 hr following a single training trial. Passive avoidance learning improved markedly with age, and retention over a 24‐hr interval was complete for all age groups. In Experiment 2, rats 19, 25, 32, and 90 to 120 days of age were trained in a simple, active avoidance task. A trials‐to‐criterion measure indicated that learning was relatively independent of age, although 19‐day rats were somewhat inferior to older rats. The occurrence of differences in passive avoidance learning through developmental ranges in age where simple active avoidance is little affected suggests that inhibition of responding may be selectively influenced by maturational variables.

In Experiment 1, rats received escapable shock upon crossing into the black side of a black-white chamber. The Ss receiving hypothermia 20 sec., 5 min., or 15 min. after the single training trial showed significantly poorer 24-hr, retention of the passive avoidance response than 60-min. delay or control Ss. In Experiment 2, severity of hypothermia was varied for groups receiving a passive avoidance training trial with inescapable shock. Cooling & to body temperatures below 75° F. resulted in retrograde amnesia, but no retention deficits were found in Ss with higher body temperatures. The data were interpreted as supporting the view that retrograde amnesia reflects impairment of consolidation processes.

No abstract

The laboratory study of attraction is based almost exclusively on verbal measures of the dependent variable. Various findings suggest that the physical distance separating two individuals indicates the degree of attraction between them. In two experiments, attitude similarity between a subject and two stooges was manipulated. Females were more attracted to and sat more closely beside a similar than a dissimilar stranger (p < .01); males were more attracted to and sat directly across from a similar rather than a dissimilar stranger (p < .02).