Kenneth J. Gilhooly, Incubation in Problem Solving and Creativity: Unconscious Processes. Routledge, 2019.
A problem has three elements: a goal, an inability to meet that goal, and a set of possible actions that could lead to the goal. Problems can be well- or ill-defined. Problems can be knowledge rich or knowledge lean, either requiring or not requiring expert knowledge. ‘Insight problems’ first require restructuring, ‘non-insight problems’ do not. ‘Set’, a tendency to solve problems in the same way each time, is an impediment to insight, as is ‘functional fixity’, a tendency to use objects in their usual way. Listing all the attributes of an object can help offset functional fixity, as it allows for greater use of obscure features for problem solving. When reaching an impasse in problem solving, or even before reaching an impasse, any of three restructuring processes come into play: elaboration, adding new information to the problem; constraint relaxation, removing the assumed limitations; and reencoding, reinterpreting part of the problem in a different way.
Graham Wallas’ stages of control theory, from 1926, offers four (or five) stages of creative thinking: preparation, incubation, illumination, and verification. Preparation is the initial stage of conscious work. Illumination or inspiration is the stage in which possible solutions emerge, followed by verification, the stage in which the idea is tested and developed. Prior to illumination or inspiration is intimation, “a feeling that a solution is imminent and that the solver should stop any current possibly distracting activity to let the Illumination occur” (p. 35). Straight-forward, well-defined problems will probably involve only the preparation and verification stages. If a problem is not so straight-forward it will likely include the incubation stage.
The incubation stage involves putting the problem aside for a time and not consciously working on it. There is a negative and positive aspect to incubation. The positive aspect is that something must happen, or else no insight would be reached. The negative component means the thinker does not think of the problem. Relaxation and distraction are two ways a thinker can abstain from thinking about the problem. Physical exercise can also enhance the benefits of mental relaxation, which is understood as mind-wandering or daydreaming.
“[T]oo much drudge work could have very negative effects by reducing the chances of fruitful unconscious work – Wallas saw this as a problem for university academics, who were expected to develop creative ideas but were also overloaded with administrative chores, even in the 1920s. I can personally vouch for the fact that this situation has not improved since 1926 and is generally felt to be ever worsening . . . Wallas felt there was a particular danger in the habit of continual passive reading which apparently was very prevalent among educated people in his day” (p. 36).
In delayed incubation, people work on a problem in preparation prior to engaging in an unrelated activity before returning to the problem. In immediate incubation, people are offered a problem but do not consciously work on it before they turn to an unrelated task. Only after this incubation period do people return to the target problem. Though some researchers feel that incubation is an illusion, there is some evidence that delayed incubation is useful for creative problems, though studies have found that it is less useful than immediate incubation.
There are three primary theories about what happens during incubation. ‘Creative worrying’ is the term given to the act of consciously working on the problem during incubation periods (even though people ‘aren’t supposed to'). The ‘fresh look approach’ is the theory that misleading strategies, assumptions, fixations and mental sets are forgotten during incubation, allowing a person to return to the problem having ‘shifted set’. Another view suggests that incubation involved unconscious processes. It is possible that each of these three mechanisms all work together during incubation.
“[B]oth mindfulness and mind-wandering can benefit creative thinking, depending on the strategies followed“ (p. 65).
Mind-wandering is an important part of problem solving. Problem solvers commonly experience an initial period of concentration followed by a spontaneous drifting-away of their thoughts to unrelated matters. This drifting-away is an unplanned incubation period. Planned incubation periods that facilitate mind-wandering have led to improved benefits of incubation in controlled experiments. Eye movement away from material associated with the problem indicates a shift of conscious awareness away from the problem toward more internal associations. Even when people do not undertake an explicit incubation period, they will often undertake these periods of ‘mini-incubation’ or ‘micro-incubation’ which contribute to creative problem solving.
According to Gilhooly, the unconscious work theory best explains the effects of immediate and delayed incubation. But what does unconscious work consist of? And how do solutions become conscious? This book breaks the issue of incubation into waking incubation and sleeping incubation. There is a general consensus (though not all believe there are any background processes in the brain) that the incubation effects of unconscious work involve spreading activation. This could lead to implicit effects and insight solutions. Sleep will intervene in any problem that takes more than one day to solve. Sleep has been shown to be beneficial for learning and memory. Though anecdotal evidence suggests that the hypnagogic and hypnopompic state, or even dream states, could be helpful for problem solving, this has yet to be adequately verified under experimental conditions. Even so, experiments do suggest “that processing during sleep either strengthened the habits acquired during familiarisation (leading to a speed up)” of problem solving, “or weakened the habits (leading to a slow down) and facilitated a re-structuring” of the problem (p. 96). Gilhooly concludes that sleep does help in creativity and insight.