Facial expression accompanying pain.

The study of facial expression accompanying pain is of both practical and theoretical importance. It has been suggested that nonverbal behavior may provide accurate information on pain states to supplement self-report and that perhaps facial expressions could even serve as accurate measures of pain in the absence of verbal report. Recent studies of specific facial expressions accompanying pain have benefited greatly from the techniques and findings of earlier research on facial expressions of emotion. These research findings also raise a number of questions concerning relationships between pain and emotion expressions, and provide some tools (e.g. direct facial measurement systems) for answering them. A review of empirical research indicates that there are distinct facial expressions which accompany acute painful experiences with some regularity, and that these expressions occur in both infants and adults, at least in Western cultures. Important areas for future research include cross-cultural studies, investigations of the circumstances under which these facial expressions occur and the possibilities for masking or falsifying them and research into facial behaviors related to chronic pain.