Elucidating the difference between mind-wandering and day-dreaming terms

Self-generated thoughts have been widely investigated in recent years, while the terms "mind-wandering" and "day-dreaming" are usually used interchangeably. But are these terms equivalent? To test this, online study participants were presented with situations of a protagonist engaged in self-generated thoughts. The scenarios differed with regard to type of situation, the activity in which the protagonist was engaged in, and the properties of the self-generated thoughts. Two different groups evaluated the same situations; one group evaluated the extent to which the protagonist mind-wandered and another the extent to which the protagonist day-dreamt. Our key findings were that the situations were perceived differently with regard to mind-wandering and day-dreaming, depending on whether self-generated thoughts occurred when the protagonist was busy with another activity and the type of self-generated thoughts. In particular, while planning, worrying, and ruminating thoughts were perceived more as mind-wandering in situations involving another activity/task, the situations without another activity/task involving recalling past events and fantasizing thoughts were perceived more as day-dreaming. In the additional experiment, we investigated laypeople's reasons for classifying the situation as mind-wandering or day-dreaming. Our results altogether indicate that mind-wandering and day-dreaming might not be fully equivalent terms.