Mind-wandering as spontaneous thought: a dynamic framework

Mind-wandering is often defined as task-unrelated or stimulus-unrelated thought. In this Review, Christoff and colleagues present a definition for mind-wandering that places more emphasis on the dynamic nature of this process. They also examine the brain networks underlying mind-wandering and its involvement in various brain disorders. Most research on mind-wandering has characterized it as a mental state with contents that are task unrelated or stimulus independent. However, the dynamics of mind-wandering — how mental states change over time — have remained largely neglected. Here, we introduce a dynamic framework for understanding mind-wandering and its relationship to the recruitment of large-scale brain networks. We propose that mind-wandering is best understood as a member of a family of spontaneous-thought phenomena that also includes creative thought and dreaming. This dynamic framework can shed new light on mental disorders that are marked by alterations in spontaneous thought, including depression, anxiety and attention deficit hyperactivity disorder.