Matters of the Mind offers an occasional look at recent research into the relationship between the mind and the body.

What people do instead of going to bed, why anxious people can’t relax, and how Twitter might be helpful in assessing loneliness have been the focus of recent studies.

Studies have linked bedtime procrastination—going to bed later than intended for no external reason—with putting off other activities, low levels of self-regulation, and fatigue.