Infants recognize identity in a dynamic facial animation that simultaneously changes its identity and expression

Recognition of facial identity and facial expression have been reported to be correlated. Previous studies using static facial photographs reported that identity recognition was not interfered by task-irrelevant change of facial expression but that expression recognition was interfered by task-irrelevant change of facial identity. In this study, we created dynamic morphing animations that simultaneously changes facial identity and expression to investigate the interaction between identity and expression recognition. We tested 7 –8-month-old infants who were around the age at which the recognition of facial expression develops. Using the familiarization–novelty preference procedure, we examined whether infants could learn identity and facial expression from morphing animation. We found that infants learned identity but not expression from the morphing animation. Our results demonstrate that the interaction between identity and expression occurs differently in infancy than in adults when both the dimension of facial identity and the expression vary simultaneously.