The effect of facial blood flow on ratings of blushing and negative affect during an embarrassing task: preliminary findings.

Expecting to blush is a common source of social anxiety, and is associated with heightened perceptions of blushing and embarrassment. To assess whether sensory cues associated with heightened facial blood flow are an additional source of anxiety, the vasodilator niacin (100mg) or placebo was administered double-blind to 33 participants, and facial blood flow was investigated when they sang a children's song. Vasodilatation during singing was greater in the niacin than placebo condition, and niacin-evoked flushing and increases in pulse rate were greater in participants with high than low fear of negative evaluation. Nevertheless, ratings of embarrassment, anxiety, blushing and facial heat were similar in both drug conditions. This dissociation implies that cognitive appraisals or negative affect overrode more subtle physiological cues of blushing during embarrassment. Clarifying how judgments about blushing are made could be crucial for correcting faulty assumptions about blushing in people who are frightened of this response.