Numerous anecdotal accounts exist of an incubation period promoting creativity and problem solving. This article examines whether incubation is an empirically verifiable phenomenon and the possible role therein of nonconscious processing. An Idea Generation Test was employed to examine (a) whether an incubation effect occurred and (b) the impact of different types of break on this effect. In the Idea Generation Test, two groups of participants were given a distracting break, during which they completed either a similar or an unrelated task, and a third group worked continuously (N = 90). The Idea Generation Test was validated against established measures of cognitive ability and personality, and was found to exhibit variance distinct from those marker tests. Most important, results demonstrated that having a break during which one works on a completely different task is more beneficial for idea production than working on a similar task or generating ideas continuously. The advantage afforded by a break cannot be accounted for in terms of relief from functional fixedness or general fatigue, and, although it may be explicable by relief from task-specific fatigue, explanations of an incubation effect in terms of nonconscious processing should be (re)considered. [ABSTRACT FROM AUTHOR]