The eyes have it: How sleep supports social and emotional development in infants

Research Summary
Saurab Faruque
Research Assistant

Infancy is a time of rapid development and learning, including processing social information such as the facial expressions of others. While previous research suggests that poor sleep impairs our ability to recognize emotional expressions in others, it is unclear how. A new study published in Nature suggests that for infants, eye contact may be the missing link.

Using eye-tracking, Dr. Wanqi Sun and colleagues recorded the amount of time 52 one-year-olds spent looking at eye-regions when shown a picture of a face with a neutral, pleasant, or unpleasant emotional expression. Each infant also wore an ankle bracelet for 7 consecutive days. The bracelet measured sleep quality: the total amount of time the baby slept, the consistency of sleep patterns, and the ability to stay asleep after falling asleep. The sleep and eye-tracking data showed that babies who had better sleep quality spent more time looking at the eye-regions of faces with emotional expressions compared to babies with poor sleep quality.

By spending less time looking at the eyes of pleasant and unpleasant emotional expressions, infants may miss out on cues that help them recognize these facial expressions. Sun suggests that this could negatively impact social and emotional development.

The researchers also made an interesting (but speculative) connection to Autism Spectrum Disorder (ASD), a neurodevelopmental disorder that affects social behavior. One hallmark characteristic of ASD is avoidance of eye contact, which has been observed in as early as two to six-month-olds who were later diagnosed with autism. According to several studies, including a recent literature review published in the Journal of Pediatric Neurosciences, between 40% and 80% of those with ASD have sleep problems. Sun’s research highlights a possible connection between sleep problems in individuals with autism, avoidance of eye-contact, and deficits in social and emotional development.