Strategies, Heuristics and Biases in Complex Problem Solving

How do instructions help people solving complex puzzles? We studied a problem solving task (Which of the 12 balls is heavier or lighter than the rest?) using detailed analyses of problem solving steps to assess what cognitive biases, heuristics and strategies were used. First, we found that all participants effectively used means-ends analysis. Second, in the absence of instructions or observation of successful solutions, participants preferred symmetrical and overly simple solution steps. Instructions and imitation effectively reduced these biases, which was important for correct solutions. Finally, instructions and imitation helped participants attend to less salient aspects of the task.