Development of responses by facial expressions and eye movements in neonates and young infants.
Eye movements and facial expressions were assessed in 177 normal neonates and infants under 150 days of age after the examiner gazed into their eyes for 20 seconds. Blinking to a threatening stimulus and turning of the eyes towards a red object near the examiner's face were tested. The eye movements abruptly changed from fine nystagmoid movements to distinct rolling movements suggesting observation of the examiner's face after 70-80 days of age. Rapid turning of the eyes towards the red object also appeared from the same age, while blinking developed gradually after 40 days of age. Most infants under 80-90 days of age knitted their brows and showed esophoria in response to the examiner's face or facial movements, but such responses gradually disappeared after 90 days of age when social smiles developed. Eye movements and facial expressions during early infancy are very informative in developmental evaluations.
D001767:Blinking; D002657:Child Development; D005133:Eye Movements; D005149:Facial Expression; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012919:Social Behavior