If you pay attention to where your mind wanders it can tell you something about your mental health.
University of Arizona researchers found ruminative individuals had negative thoughts that lasted longer than positive thoughts, and those negative thoughts became progressively narrower in topic over time. Other people thought about positive things, and positive topics or goals they wanted to reach in their downtime.
Study co-author Jessica Andrews-Hanna says,
Eventually, we hope to connect the psychological characteristics of idle thought to the biological patterns of activity and connectivity changing across time to provide a fuller picture of consciousness and mental health.