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Groups of rats were exposed to training procedures that produce leverpress avoidance (Experiment 1) or escape (Experiment 2) behaviors. Plasma samples were obtained by decapitation after 30 sessions, and corticosterone concentrations were determined and compared with those of corresponding yoked and nonshocked (time-in-box) groups. The mean corticosterone level of the “avoiders” was lower than that of their yoked mates and not different from that of their non-shocked mates. This indicated a reduction in their arousal level with mastery of the avoidance response, which could not be accounted for by the reduction in numbers of shocks received. The mean corticosterone level of the “escapers” was as high as that of their yoked mates, and both levels were higher than that of the nonshocked group.

The serum glucose levels of 90-day-old and 1-year-old male Spontaneously Hypertensive (SHR) and Sprague-Dawley (SD) rats were examined in two experiments. Half of each strain and age group were exposed to 51-min daily sessions of unpredictable, uncontrollable grid shocks during a 30-day period prior to sampling via decapitation. The other half remained undisturbed in their cages. Dietary intake was equated across all groups within each strain. Stress-induced increases were observed in both age groups, in both strains (ps < .05). The SHRs showed an age × stress interaction with old, stressed animals having the highest levels (ps < .05). Both younger SD groups had higher levels than corresponding older SD groups (ps < .05).

Need achievement as measured by the Edwards scale was used to select high-need (HN) and low-need (LN) individuals. HN Ss were found to be superior in rotary pursuit tracking. Both HN and LN Ss, when told their performance was above average, showed less subsequent performance decrement and reminiscence than did Ss who were told their performance was below average.

Two groups of 12 rats were run in a single choice maze where one arm contained one unit of food 100% of the time, the other two units 50% of the time. For Group S one unit was two 45 mg pellets; for Group L one unit was 12 pellets. Group L acquired a significant preference for the 1 unit-100% side, and Group S acquired a significant preference for the 2 units-50% side.

The hypothesis was tested that partial reinforcement results in increased resistance to extinction because stimuli produced by fractional anticipatory frustration responses (rF) become conditioned to adient instrumental responses during training. On the assumption that alcohol diminishes or inhibits rF the drug was administered during training trials. Extinction findings failed to support the hypothesis.