Are smiles a sign of happiness? Spontaneous expressions of judo winners

Which is the strongest predictor of Duchenne smiles? Is it emotion or sociality? Two field studies on the production of facial behavior by winning judo fighters (N = 174) are presented, testing if judo fighters smiled while being happy or while they were engaged in social interaction with the audience. Our studies simultaneously meet important methodological requirements: intense emotions; precise moment-to-moment coding of facial expressions; behavioral records long enough to allow smiles to unfold; discrimination between records of interactive and non-interactive behavior, and self-reports of emotional experience after winning a medal. We found that Duchenne smiles were not a necessary sign of happiness. Although all the judo fighters won their respective matches, they displayed a very low proportion of Duchenne smiles (.15 in Study 1, and .21 in Study 2). Being engaged in social interaction (communicative gestures with arms and hands while facing the audience) was found to be the strongest predictor for the occurrence of Duchenne smiles. Our studies provide support for the view that facial expressions are tools for social interaction (Behavioral Ecology Theory), rather than read-outs of basic emotions (Facial Expression Program).