A common suggestion for handling impasses in problem solving is to put the problem aside, by “sleeping on it”, rather than by consciously undertaking a different task and allowing unconscious incubation processes to take effect while still awake. In real life, a sleep period will intervene for any problem that is not solved within a single waking day and so such problems will be open to possible effects of sleeping on them. From a practical as well as a theoretical point of view, it is important then to consider sleep effects.