| Abstract: | An investigation was carried out of the effect of undernourishing rats during much of gestation and throughout the whole suckling period on their behavior in a passive avoidance situation. All young were fed ad libitum from 21 days of age. Passive avoidance tests were done at 30 and 31 days in a two-compartment box. On the first test normal rats tended to cross between compartments more promptly than previously underfed rats. Cross-over latency was always greater on the second test than on the first. There were no significant differences in test 2 latency or in the ratio, test 2 latency/test 1 latency, between sexes, between normal and previously undernourished rats, between groups with 2-min and 24-hr interest intervals, or between master and yoked control rats. The last finding indicates that the apparent passive avoidance response may have been either nonspecific ‘freezing’ behavior following unpleasant stimulation, or inhibition specifically of movement, due to its association with shock. |
