Six-month-old infant long sleepers prefer a human face.

ABSTRACT

BACKGROUND: Sleep is known to influence socio-emotional regulation among children and preschoolers, whereas little is known about the association between sleep and social preference during infancy. METHODS: In the current study, habitual sleep of 49 infants aged around six months old were surveyed by questionnaire, and their social preference was revealed by their preferential gaze in three conditions (1) a human face paired with an object (ie, a cup), (2) a human face paired with an animal face (ie, a dog), and (3) a dog face paired with a cup. RESULTS: In general, images with richer social information (ie, a human face and dog) attracted infants' gaze significantly more than nonsocial images (ie, cup). Infants with shorter sleep duration (ie, <13 h a day) show a significant reduction in their preference toward a human face when paired with a dog than infants with longer sleep duration. CONCLUSIONS: Our findings suggest an early positive link between sleep duration and preference towards socially rich stimuli (eg, a human face) during infancy.