Gender and Ethnic Differences in Smiling: A Yearbook Photographs Analysis from Kindergarten Through 12th Grade

Previous research has demonstrated that women smile more frequently and more broadly than men (Abel 2002; LaFrance et al. 2003). However, little research has focused specifically on the age at which this gender difference first emerges, and even less
on the ethnic differences in smiling. This study attempts to identify the age when gender differences in smiling emerge among
European American and African American children and teenagers. Additionally, we looked at the level of diversity within each
school and its relation to smiling behavior. In total, 18,201 yearbook photographs ranging from kindergarten through 12th
grade from 17 schools in the state of Michigan were evaluated for smile type: full smile, partial smile or no smile. Results
suggest that a significant gender difference in smiling emerges around age 11. In contrast to other studies (e.g., LaFrance
et al. 2003) and our own expectations, differences in smiling were found to be larger between African American boys and girls than between
European American boys and girls. In addition, we found that African American girls’ smiling behavior did not differ as a
function of school diversity while African American boys from predominantly African American schools displayed less smiling
compared to those from mixed or predominantly European-American schools. This study provides insight into the emergence and
progression of gender differences in smiling and indicates that gender as well as ethnicity and ethnic diversity are influential
factors in smiling behavior.