Effects and aftereffects of stressor expectations.

Is stressor exposure necessary to produce "stress" effects, or can these effects result from stressor anticipation alone? The present research explores whether it is possible to obtain "stress responses" during and after the period in which stressor exposure is being anticipated. In the first study, the expectation of submerging one's hand in ice water resulted in decreased frustration tolerance and increased blood pressure when compared with control groups not expecting this stressor. A second study replicated and extended these results to show that the expectation of control over the stressor ameliorates the negative impact of stressor expectation. The second study also examined the aftereffects of expectations. Particularly, it found that despite being relieved of the expectation that they would immerse their hand in ice water, subjects who had expected stressor exposure had decreased frustration tolerance when compared with either subjects who had expected a nonstressful procedure or those who had expected to have control over stressor termination. A third study, using noise as the expected stressor, replicated both the aftereffect of the anticipation period and the moderation of that effect by perceived control. The discussion (a) focuses on the implications of this work for understanding why aftereffects occur and (b) proposes that previously observed stressor exposure effects may in fact be postexpectation effects.