The contingent smile: a meta-analysis of sex differences in smiling.

The authors present a meta-analysis of sex differences in smiling based on 448 effect sizes derivedfrom 162 research reports. There was a statistically significant tendency for women and adolescent girls to smile more than men and adolescent boys (d = 0.41). The authors hypothesized that sex differences in smiling would be larger when concerns about gender-appropriate behavior were made more conspicuous, situational constraints were absent or ambiguous, or emotion (especially negative) was salient. It was also predicted that the size of the sex difference in smiling would vary by culture and age. Moderator analysis supported these predictions. Although men tend to smile less than women, the degree to which this is so is contingent on rules and roles.