PATTERNS OF CORTICAL ELECTROPHYSIOLOGY AND AUTONOMIC ACTIVITY IN ADULTS SHYNESS AND SOCIABILITY

We examined differences in brain electrical activity (EEG), heart rate (EKG), heart rate variability, and behavior among 40 young women who were selected for high (HI) and low (LO) self-ratings of shyness and s ociability. EEG and EKG were continuously recorded for 6 min from each subject, just prior to an expected novel social encounter. Each subje ct was also observed unobtrusively for 5 min during the social encount er. Analyses indicated that the pattern of frontal EEG asymmetry was r elated to sociability, but not to shyness. LOSOCIABLE subjects display ed greater relative right mid-frontal activation while HISOCIABLE subj ects displayed greater relative left mid-frontal activation. A signifi cant shy X sociable interaction was found for parietal asymmetry and f or measures of heart rate and heart rate variability. LOSHY/HISOCIABLE subjects displayed greater relative right parietal activation while L OSHY/LOSOCIABLE subjects displayed greater relative left parietal acti vation. And HISHY/HISOCIABLE subjects displayed a significantly higher and more stable (less variable) heart rate than HISHY/LOSOCIABLE and LOSHY/ HISOCIABLE subjects. Analyses also indicated that LOSOCIABLE su bjects displayed significantly more signs of nonverbal social avoidanc e as compared with HISOCIABLE subjects. The present findings suggest t hat shyness and sociability may be subserved by different neurophysiol ogical systems.