Mind-wandering

Mind-wandering (sometimes referred to as task-unrelated thought) is the experience of thoughts not remaining on a single topic for a long period of time, particularly when people are engaged in an attention-demanding task.

Mind-wandering tends to occur during driving, reading and other activities where vigilance may be low. In these situations, people do not remember what happened in the surrounding environment because they are pre-occupied with their thoughts. This is known as the decoupling hypothesis. Studies using event-related potentials (ERPs) have quantified the extent that mind-wandering reduces the cortical processing of the external environment. When thoughts are unrelated to the task at hand, the brain processes both task relevant and unrelated sensory information in a less detailed manner.