Why the Mind Wanders

The mind wanders. Ideally, it does not wander so far that it forgets it is reading this chapter. But consciousness does have an inevitable drift, changing its contents moment by moment. The focus seems to move relentlessly, shimmering and fidgeting no matter how hard we may try to concentrate on a thought, preserve an image, or otherwise freeze the instant. Not only does it seem quite impossible to hold a particular thought or percept fully in mind for an indefinite period, it also seems futile to attempt to keep consciousness away from a chosen target by fixing our minds on something else. Consciousness simply cannot hold itself still. The persistent flow of consciousness prompted James (1890) to use the descriptive metaphor of a "stream," and this quality has been recognized by contemporary commentators as one of the key phenomena of consciousness that must be explained (e.g., Baars, 1988; Johnson-Laird, 1988). Why, after all, must it be like this? Why can't we just push the psychological equivalent of a "still frame" button on a videotape recorder and stop all this wriggling and hopping about? The purpose of this chapter is to suggest a theoretical framework within which the necessity of a wandering consciousness is made clear, and through which predictions can be made about where the mind will wander. In this framework, the constant metamorphosis of consciousness turns