Abstract:
A meta-analytic review of empirical studies that have investigated incubation effects on problem solving
is reported. Although some researchers have reported increased solution rates after an incubation period
(i.e., a period of time in which a problem is set aside prior to further attempts to solve), others have failed
to find effects. The analysis examined the contributions of moderators such as problem type, presence of
solution-relevant or misleading cues, and lengths of preparation and incubation periods to incubation
effect sizes. The authors identified a positive incubation effect, with divergent thinking tasks benefiting
more than linguistic and visual insight tasks from incubation. Longer preparation periods gave a greater
incubation effect, whereas filling an incubation period with high cognitive demand tasks gave a smaller
incubation effect. Surprisingly, low cognitive demand tasks yielded a stronger incubation effect than did
rest during an incubation period when solving linguistic insight problems. The existence of multiple types
of incubation effect provides evidence for differential invocation of knowledge-based vs. strategic
solution processes across different classes of problem, and it suggests that the conditions under which
incubation can be used as a practical technique for enhancing problem solving must be designed with
care.