Infants readily re-enact others' intended actions during the second year of life. However, the role of emotion in appreciating others' intentions and how this understanding develops in infancy remains unstudied. In the present study, 15- and 18-month-old infants observed an experimenter repeatedly attempt but fail to produce a target action on an object and express either frustration or neutral affect after each attempt. Analyses of infants' responses revealed that 18-month-old infants, but not 15-month-olds, produced more target actions in the frustration condition than the neutral condition. These results suggest that infants use emotional communication to disambiguate and re-enact others' intended actions and that this ability develops in the second year of life.
Keywords: Imitation; emotion; infancy; intentionality; social cognition.