The effects of actual and potential stressor control on physiological and self-reported stress responses

Two broad groups of theories offer explanations for the stress modifying effects of stressor control. One group of theories attributes the stress modifying effects of control to the predictive information furnished by the controlling action. The second, regards the effects of stressor control as being independent of predictability. The minimax theory belongs to this second group. It predicts stress reduction in the experimental group when all factors are held constant across experimental and comparison conditions, but where only subjects in the experimental group have stressor control. Two experiments were conducted to test this prediction. Actual control over brief bursts of loud noise was available to subjects in the experimental group of the first experiment. In the second, the effects of potential (but unexercised) control were examined. In both experiments subjects in the comparison group had no control over the stressors. However, they were exposed to the same pattern of stimulation, and had the same amount of predictive information as their experimental group counterparts. Experimental and comparison groups were matched on five organismic variables, viz. age, sex, Neurorticism, Extraversion, Desirability of Control, and coping style. Physiological and self-reported stress responses were recorded during both stressor anticipation and impact periods. Less anticipatory physiological stress was observed in the experimental than in the comparison groups in both experiments. Intergroup differences on the remaining dependent variables were not reliable. The minimax theory was partially supported. Coping style was included as an organismic variable in a number of further analyses. These revealed that while behavioural control led to anticipatory physiological stress reduction, the use of cognitive nonvigilant coping strategies led to a reduction in anticipatory self-reported stress. Interactions between stressor control and coping style were also observed. These interactions suggested that stress reduction may be enhanced by using different coping strategies in different situations. The clinical implications of this congruence model were discussed.