Frontal brain electrical asymmetry and cardiac vagal tone predict biased attention to social threat.

Individual differences in attention biases for motivationally significant stimuli have been reported in clinical and normative populations. Few studies, however, have attempted to examine potential biological mechanisms underlying differences in the cognitive processing of emotional stimuli. The present study examined the extent to which two well-validated psychophysiological vulnerability markers of affective style [i.e., frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone] predicted biased attention toward rapid presentations (approximately 250 ms) of angry and happy facial expressions. We found that right frontal EEG asymmetry and low cardiac vagal tone, taken together, predicted approximately 37% of the variability in attentional vigilance for angry faces. Frontal EEG asymmetry and cardiac vagal tone did not predict attention for happy faces, independently of each other. Our results provide preliminary evidence that two well established psychophysiological indicators of affective style bias early processing of motivationally salient stimuli.