Activation of the arousal response and impairment of performance increase with anxiety and stressor intensity

The purpose of this study was to determine the effect of trait anxiety and stressor intensity on arousal and motor performance during a pinch task. We examined the steadiness of a precision task in the presence and absence of an imposed stressor on subjects with moderate and low trait anxiety. Subjects with the 26 highest and 14 lowest anxiety scores were assigned to one of three groups: a control group (5 women, 5 men), a moderate-anxiety group (8 women, 8 men), or a low-anxiety group (7 women, 7 men). Subjects in the anxiety groups received electric shocks and experienced significant increases in cognitive and physiological arousal compared with baseline and control subjects, especially subjects in the moderate-anxiety group. Heart rate, systolic blood pressure, and electrodermal activity were elevated during the stressor, whereas diastolic blood pressure was unchanged. Cognitive and physiological arousal tended to increase with stressor intensity and was accompanied by changes in steadiness. Although steadiness was markedly reduced with the highest intensity of shock, the average electromyogram activity was unaffected by the stressor. These findings indicate that the increase in arousal and the impairment of steadiness increased with trait anxiety and with the intensity of the noxious stimulus.