This is an exciting time for mind-wandering in psychology. In the past decade, research has shed much light on the mental state of inattention. Amidst all this research, however, we want to make sure daydreaming doesn’t get overlooked. Here we trace the development of research on daydreaming, and place it within the context of modern research on mind-wandering. We hope this article makes important distinctions which may further future research and theory on these important topics. We want to emphasize the adaptive value of attending to your own internal stream of consciousness—regardless of the label psychologists decide to put on the experience.

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Heavily influenced by the writings of William James, Sigmund Freud, and Kurt Lewin, Jerome L. Singer started to develop his research program on daydreaming and the stream of consciousness at Teachers College, Columbia University in the 50’s. The German-American psychologist Kurt Lewin argued for different “levels of reality” —shifts from responses directly evoked by “environmental forces” to possibilities and fantasy. Lewin’s ideas, along with the writings of William James, and Freud’s emphasis upon clinical free association all encouraged Singer’s belief that systematic experimentation was key to exploring “the mind within”.

Singer and his assistant and later close collaborator, John Antrobus, began their study of “decoupled attention” by interviewing volunteer “normal” adults about their daydreams and the circumstances under which they drifted into daydreams. What immediately became clear was that daydreaming is a normal, widespread, human phenomenon that people are aware of consciously and can report reliably on questionnaires. Large numbers of people from different walks of society, gender, and ethnicity reported considerable daydreaming in their daily lives. Additionally, those who reported they daydreamed more in their daily lives also showed similar patterns under systematic laboratory conditions. Singer reported on his exciting findings in his seminal 1966 book “Daydreaming: An Introduction to the Experimental Study of Inner Experience”.

To capture these ongoing mental processes in the laboratory, Singer and his colleagues used carefully controlled procedures based on signal detection research. With this methodology, participants are seated in a soundproof booth and different tones are presented through headphones. The individual is requested to press a button whenever a high or low tone is presented. Correct signal detections are financially rewarded. Every 15 seconds they are also asked to report whether they experienced what psychologist Leonard Giambra refers to as “task-unrelated images or thought” (TUITS). Analysis of the content revealed that people’s task-unrelated thoughts ranged widely from fantasies about the experimenters to highly personal memories or daydreams.

Moving beyond the signal detection approach, Singer and his colleagues used “thought sampling” methods, in which participants were interrupted either during the experiment or in their daily lives by a paging device, in which they had to immediately report their thoughts and emotions. This methodology led to all sorts of interesting research and theory. Another early pioneer was Eric Klinger, whose research showed that most people’s daydreams and night dreams reflect “current concerns” ranging from constant thoughts of incomplete tasks to unresolved desires, ranging from sexual and social strivings to altruistic or to revenge urges and the panoply of human motivations.

These early investigators also noticed that people differed in their styles of daydreaming. To capture these individual differences, Singer and his colleagues developed The Imaginal Processes Inventory (IPI). For a full list of the correlates of this inventory, see this book chapter. Three main styles of daydreaming emerged from the scales: Positive-Constructive Daydreaming (representing playful, wishful and constructive imagery), Guilty-Dysphoric Daydreaming (representing obsessive, anguished fantasies), and Poor Attentional Control (representing the inability to concentrate on ongoing thought or external tasks). Psychologist Lenoard Giambra and his colleagues made an important contribution to the literature by using the IPI to measure daydreaming patterns across the lifespan.

Tang and Singer found that these three different styles of daydreaming were associated with different basic personality traits drawn from the well studied “Big Five”. A Positive-Constructive daydreaming style was associated with Openness to Experience, reflecting a curiosity, sensitivity, and exploration of ideas, feelings, and sensations. Poor Attentional Control was related to low levels of Conscientiousness, and Guilty-Dysphoric daydreaming was positively related to neuroticism. Tang and Singer concluded: “The convergence of these models…suggests that these factorial structures are probably reflections of something fundamental about our brain and our physiological experience.” It turns out, they were right.

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With the emergence of modern cognitive neuroscience research, came the ability to physically see what happens in our brain when we turn our attention inward. Current neuroimaging research supports Singer’s idea, proposed in his 1966 book, that daydreaming is the default mental state of the human mind. Researchers have discovered a brain network—the default network— which consists mainly of communication among the medial temporal lobe, and the medial prefrontal and posterior cingulate cortices. Research shows that this particular brain network is related to various aspects of our self, such as our self-representations, dreams, imaginations, current concerns, autobiographical memories, and perspective-taking ability. Those with higher default network activity during rest have a tendency to “mind-wander” more frequently in their daily lives.