Do Different Infant Smiles Reflect Different Positive Emotions?

Different types of infant smiles in the family of positive emotions were investigated during two mother‐infant games: peekaboo and tickle. There were 27 6‐month‐old infants and 28 12‐month‐olds. Infant smiles were coded as simple (lip corner retraction only), Duchenne (simple plus cheek raising), play (simple plus jaw drop), and duplay (simple plus cheek raise and jaw drop). Results show that each type of smile has a systematic pattern of association with the game (peekaboo or tickle), component (setup or climax), trial (six trials for each game), and the direction of the infant’s gaze. No significant age differences were found. We conclude that when smiling, infants may experience qualitatively different kinds of enjoyment during these two games: enjoyment of readiness to engage in play (simple smiles while gazing at mother during peekaboo), enjoyment of relief (simple smiles while gazing away from mother after being tickled), enjoyment of participation and agency (Duchenne smiles with gaze at mother during the climax of early tickle game trials), enjoyment of escape (Duchenne smiles while gazing away during tickle climax), and enjoyment of build‐up (duplay smiles during the climax of later trials). These findings show that the same facial action, smiling, can reflect different positive emotions depending upon cooccurring facial actions and the dynamics of the social process, and that the positive emotional experience of infants as young as six months is more complex than previously reported.