Spontaneous thought has recently been defined as a state of reduced constraints on the mind, and it encompasses a range of experiences such as mind-wandering, day and night dreaming, creative idea generation, and others. While its day-to-day benefits have been explored for some time, its clinical implications have been understudied, and for the most part have been limited to potential detrimental effects on mood. We propose that spontaneous thought has a wider variety of clinical effects, as well as a number of potential therapeutic benefits—affording the opportunity to address suppressed or repressed material, facilitating therapeutic insights, and promoting general relaxation. Its unconstrained mode may not be without clinical risks, however. Within literature discussing meditation, sleep, relaxation, and sensory deprivation—activities that promote unconstrained attention—evidence suggests that some individuals may become destabilized, or face a worsening of symptoms in some circumstances. More research needs to be done to clarify the mediating factors that could result in these divergent outcomes.

Although mind-wandering has received increased attention in the field of cognitive neuroscience, definitions have not always aligned. Most have emphasized the contents of thought, treating it as synonymous with either task-unrelated thought or stimulus-independent thought. Such definitions miss an important aspect of what it means to let one’s mind wander: the easeful way that thoughts move about. A more recent definition looks, instead, at the dynamics of thought—the way that thoughts unfold over time—positioning mind-wandering as a type of spontaneous thought. By doing so, it is therefore more readily equipped to incorporate this quality of ease. While the term mind-wandering can sometimes refer either to a momentary event or to an ongoing activity, both usages, this chapter argues, will be unsatisfactory if they do not address this gentle mode of movement. Some benefits that ease can provide for future research are proposed.

Mind wandering is frequently defined as task-unrelated or perceptually decoupled thought. However, these definitions may not capture the dynamic features of a wandering mind, such as its tendency to 'move freely'. Here we test the relationship between three theoretically dissociable dimensions of thought: freedom of movement in thought, task-relatedness, and perceptual decoupling (i.e., lack of awareness of surroundings). Using everyday life experience sampling, thought probes were randomly delivered to participants' phones for ten days. Results revealed weak intra-individual correlations between freedom of movement in thought and task-unrelatedness, as well as perceptual decoupling. Within our dataset, over 40% of thoughts would have been misclassified under the assumption that off-task thought is inherently freely moving. Overall, freedom of movement appears to be an independent dimension of thought that is not captured by the two most common measures of mind wandering. Future work focusing on the dynamics of thought may be crucial for improving our understanding of the wandering mind.