Communication of affect through facial expressions in humans.

Women, who were more expressive, tended to be less psychophysiologically responsive (externalizers) and men, who were less expressive, tended to be more psychophysiologically responsive (internalizers).

“Buck and colleagues (Buck et al., 1974; Buck et al., 1972) found that women, who were more expressive, tended to be less psychophysiologically responsive (labeled externalizers) and men, who were less expressive, tended to be more psychophysiologically responsive (labeled internalizers).”

Although women were more expressive than men, this expressivity advantage is not entirely consistent with the internalizer-externalizer framework proposed by Buck and colleagues.

“Although women were more expressive than men, this expressivity advantage is not entirely consistent with the internalizer–externalizer framework proposed by Buck and colleagues (Buck et al., 1974; Buck et al., 1972).”

One hypothesis holds that women tend to be externalizers in that their display of emotion tends to be primarily in the expressive domain, and men tend to be internalizers in that their display of emotion is manifested primarily via the psychophysiological domain.

“One hypothesis (Buck et al., 1974; Buck et al., 1972) holds that women tend to be externalizers in that their display of emotion tends to be primarily in the expressive domain. By contrast, men tend to be internalizers in that their display of emotion is manifested primarily via the psychophysiological domain.”