Sleep restriction reduces positive social emotions and desire to connect with others.

Feeling connected with others and experiencing positive interpersonal interactions is associated with physical health and psychological functioning. Despite the importance of social experiences, experimental studies investigating how sleep impacts social connections and positive social experiences are limited. The current study sought to examine how sleep loss impacted social motivation and emotions. Healthy emerging adults (N = 53; 83% female, ages 18-28 years) were randomly assigned to one night of sleep restriction (4h time in bed) or typical sleep (8 h time in bed). Following the experimental night, participants reported on their desire to pursue social connections, and completed a reflection task where they wrote about something generous someone did for them. After the reflection, participants reported on their positive and negative social emotions (gratitude, connectedness, guilt, indebtedness). Coding of the reflections was conducted to extract emotional tone and social words used. Sleep restricted participants reported reduced motivation to pursue social connections, and less gratitude and feelings of connectedness after the reflection compared to the control condition. Sleep restricted participants also used fewer socially-oriented words (i.e. words focused on other people) when reflecting on this interpersonal event. No differences emerged in guilt or indebtedness or emotional tone of the reflection. Findings suggest that sleep loss may decrease desire to engage in social interactions and reduces positive social emotions. These findings expand the limited body of research on sleep and social functioning by examining the impact of partial sleep restriction on social motivation, and on the experience of social emotions within a positive interpersonal context.