Information, choice, and reactions to stress: a field experiment in a blood bank with laboratory analogue.

Two experiments examined the effects of various operations of personal control on reactions to stress. The first study incorporated two features into the blood drawing procedure at a blood bank: providing donors with accurate information and allowing donors to choose the arm to be used. Measurement of nurses' actions to prevent donors from fainting and self-reports of discomfort revealed that the combination of choice and information was somewhat effective in reducing distress. However, providing either information or choice alone was more effective. In a second laboratory study using a cold pressor stimulus as stressor, subjects given a choice (the option to terminate the aversive stimulus and choice of hand used) showed a reduction of aftereffects on a measure of attention to detail. Subjects given information but not choice also showed this reduction. Combining information and choice was no different from either treatment alone. Taken together, the results of both studies indicate that moderate levels of choice and information are optimal for coping with stress. An explanation was suggested based on a contextually determined relationship amomg choice, information, and perceived control.