Do smiles have a face value? Panel evidence from Amazonian Indians

Research suggests that physical attractiveness pays off. We estimate the returns to one dimension of attractiveness: smiling. Across cultures, genuine smiles produce a halo effect that correlate with friendliness, kindness, and altruism. In experimental and observational studies in industrial economies, the frequency of smiling correlates with greater trust, cooperation, and earnings. Do results hold up in other cultures after controlling for the role of unobserved third variables? Drawing on five-quarter panel data from 329 women and 350 men over 16 years of age in a foraging and farming society of the Bolivian Amazon, we estimate the returns to smiling using body-mass index (BMI; kg/m²) as a proxy for income. Subjects who smiled, smiled and laughed, and laughed openly during interviews had 2.4%, 3.1%, and 5.4% higher BMI than subjects who neither smiled nor laughed. The mirth premium is robust to many econometric specifications, but not to the use of a person-fixed effect model, suggesting that the positive correlation between smiling and desirable outcomes found in industrial economies and in this study picks up the role of unobserved and unmeasured fixed attributes of subjects (e.g., stable physiological and psychological attributes). Subjects who smiled had more social capital and better self-perceived health than those who did not smile; these intermediary variables might explain the positive correlation between smiling and BMI. Smiling did not correlate with wages nor access to credit.