Changes in pupil size can reflect social interest or affect, and tend to get mimicked by observers during eye contact. Pupil mimicry has recently been observed in young infants, whereas it is unkno...

ABSTRACTAdults perceive emotional expressions categorically, with discrimination being faster and more accurate between expressions from different emotion categories than between two stimuli from the same category. The current study sought to test whether facial expressions of happiness and fear are perceived categorically by pre-verbal infants, using a new stimulus set that was shown to yield categorical perception in adult observers. These stimuli were then used with 7-month-old infants using a habituation and visual preference paradigm. Infants were first habituated to an (...) expression of one emotion, then presented with the same expression paired with a novel expression either from the same emotion category or from a different emotion category. After habituation to fear, infants displayed a novelty preference for pairs of between-category expressions, but n... (shrink)