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

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.