RELIABILITY OF PSYCHOPHYSIOLOGICAL RESPONDING AS A FUNCTION OF TRAIT ANXIETY

This study examined the temporal stability of three psychophysiologica l responses (frontal electromyographic activity, hand surface temperat ure, and heart rate) recorded over four sessions (days 1, 2, 8, and 28 ) on 34 subjects, 17 with high Spielberger Trait Anxiety Inventory sco res and 17 with low scores. Each session consisted of a 20-minute adap tation period, a baseline condition, and two stressors (one cognitive, the other physical). Two forms of reliability coefficients were emplo yed, intraclass correlations and Pearson Product Moment; the two types of reliability coefficients arrived at the same conclusions. Results indicated that reliability coefficients for the two anxiety groups did not differ on frontal EMG or heart rate responses; however, hand surf ace temperature responding was considerably less reliable for high anx ious individuals than low anxious individuals. Reliability coefficient s on absolute scores were, for the most part, reliable. Treating the r esponses as relative measures (percent change from baseline or simple change scores from baseline) produced smaller and less reliable coeffi cients. Magnitudes of the three physiological responses did not signif icantly differ as a function of high or low trait anxiety. Findings ar e discussed in terms of their clinical, as well as basic psychophysiol ogical, importance.