Incubation in problem solving as a context effect

Anagrams were used to test the hypothesis that incubation is the result of a change in context between two attempts at a problem. The context was manipulated between two sessions of work on the anagrams by presenting word searches containing words from a single category (either animals or fruit and vegetables) prior to each session of problem solving. Some of the anagrams had solutions from one of these two categories; these were compared with distracters, the solutions of which belonged to neither category. The anagrams subject to the context manipulation showed an incubation effect (superior performance for items attempted in two sessions relative to controls attempted in only one session) whereas distracters did not, thus supporting the hypothesis.