The mental stress test protocol is used extensively in research, but different laboratories often employ different stress tasks, utilize different dependent variables to index the stress response, and perform different transformations on the gathered data. The present study determined the test‐retest reliability of 11 cardiovascular dependent variables during a resting baseline and three common stress tasks: playing a video game, performing a choice reaction‐time test, and performing a cold‐pressor test. Sixty healthy, middle‐aged males underwent testing twice, approximately three months apart. Instructions were delivered via videotape and data were gathered on‐line by computer to ensure a standard laboratory environment. Each task elicited significant increases in blood pressure, vascular rigidity, LVET, heart rate, and stroke volume. In addition, the cold‐pressor test led to increases in total systemic resistance and mean systolic ejection rate. The absolute levels of the 11 dependent variables were correlated across tasks (partial r, baseline removed, = .06 to .69, 32 of 33 comparisons significant at p<.05), indicating that reactivity to stress generalizes across alternate test forms. The absolute levels also showed significant test‐retest reliability (r= .32 to .82; 40 of 44 comparisons significant at p<.05). In addition, for 19 of 33 comparisons, absolute levels showed greater test‐retest reliability than change scores derived by subtracting the initial resting baseline value from the stress‐task value. Finally, blood pressures taken during the stress tests were more highly correlated with the average blood pressures measured via ambulatory monitoring than casual office pressures, suggesting that such stress values may more accurately reflect average blood pressure.

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The present study was designed to assess whether the physiological correlates of learned helplessness are similar to the physiological response patterns found in naturally occurring depression. One group of subjects was pretreated with a series of inescapable aversive tones, and the degree of impairment measured on a subsequent solvable anagram solution task. These subjects were compared to a group pretreated with escapable aversive tones, and a control group which passively listened to the tones without attempting to escape them. Half of the subjects in each group were depressed as measured on the Beck Depression Inventory; the other half were nondepressed. Results indicated that depressed‐control group subjects demonstrated impaired performance at solving anagrams relative to nondepressed‐control group subjects. Inescapable noise produced parallel deficits in nondepressed subjects, thus demonstrating a similarity of impairment in naturally occurring depression and laboratory‐induced learned helplessness. More importantly, findings indicated that learned helplessness was associated with less phasic skin conductance responding, while depression was associated with greater responding to uncontrollable aversive events. These data suggest that there may be different underlying deficits involved in depression and learned helplessness.

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Eight subjects were taught to decrease their heart rates via biofeedback training. Four of these received contingently faded, beat-by-beat analogue feedback and contingent reinforcement each time their performance met a specified and adjusting criterion. The other four received continuous, beat-by-beat analogue feedback, but not the contingent reinforcement. Subjects in the two groups were yoked to ensure equal densities of reinforcement. Subjects in the first group were asked to decrease heart rates 15% from baseline and were then trained using only 75%, 50% and 25% of beat-by-beat feedback. It was hypothesized that the immediate reinforcement of appropriate behavior and the contingent fading (following mastery) of feedback would aid in the generalization of the response. Following completion of all criterion steps or 10 training sessions, whichever came first, all subjects were tested with no feedback and no contingent reinforcement. The group receiving contingently faded feedback training showed a significantly greater heart rate decrease in the training sessions and also the test session. These results were interpreted as indicating that biofeedback can be conceptualized as an operant conditioning paradigm, and that the use of operant techniques may help subjects produce clinically significant changes.