Gender Differences in the Form and Function of Naturally Occurring Smiles

Through their nuanced ability to reinforce, reassure, and judge, smiles accomplish many tasks in daily interactions. A recent approach proposes that there are at least three distinct types of smiles: reward, affiliation, and dominance, which are predicted to take different physical forms and serve unique functions in social communication. Although American women are socialized to smile more often than men, it is possible that gender differences in smile behavior depend upon social context. For instance, since it is more acceptable for men to convey status, men may produce smiles with more pronounced dominance features than women. Conversely, since women are socialized to convey harmlessness, women may produce smiles with stronger affiliation features than men. To test these hypotheses, we filmed participant pairs interacting while watching humorous videos relevant to the tasks of reward, affiliation, and dominance. We extracted all visible smiles and quantified their physical features using automated face coding software. As expected, female participants smiled more often in the affiliation context and less in the dominance context and displayed smiles with more affiliation features than males overall. Furthermore, participants’ smiles in the dominance context contained more features characteristic of dominance when they were interacting with an opposite-gender partner. This study—the first to examine naturally-elicited smiles in reward, affiliation, and dominance contexts—suggests the relationship between gender and smiling norms is nuanced and depends on the smiler’s communicative intent.