In his book on unified theories of cognition, Newell (1990) points out that there are two layers of problem solving—applying a strategy to the problem at hand, and selecting and monitoring that strategy. Good problem solving, Newell observed, often depends as much on the selection and monitoring of a strategy as on its execution. The term metacognition (literally “thinking about thinking”) is commonly used to refer to the selection and monitoring processes, as well as to more general activities of reflecting on and directing one’s own thinking.
Experts have strong metacognitive skills (Hatano, 1990). They monitor their problem solving, question limitations in their knowledge, and avoid overly simplistic interpretations of a problem. In the course of learning and problem solving, experts display certain kinds of regulatory performance, such as knowing when to apply a procedure or rule, predicting the correctness or outcomes of an action, planning ahead, and efficiently apportioning cognitive resources and time. This capability for self-regulation and self-instruction enables advanced learners to profit a great deal from work and practice by themselves and in group efforts.
Metacognition depends on two things: knowing one’s mental capabilities and being able to step back from problem-solving activities to evaluate one’s progress. Consider the familiar situation of forgetting the name of a person to whom one was introduced only a few minutes ago. There are simple metacognitive tricks for avoiding this situation, including asking the person for a business card and then reading it immediately instead of putting it in one’s pocket. Metacognition is crucial to effective thinking and competent performance. Studies of metacognition have shown that people who monitor their own understanding during the learning phase of an experiment show better recall performance when their memories are tested (Nelson, 1996). Similar metacognitive strategies distinguish stronger from less competent learners. Strong learners can explain which strategies they used to solve a problem and why, while less competent students monitor their own thinking sporadically and ineffectively and offer incomplete explanations (Chi, Bassok, Lewis, Reiman, and Glaser, 1989; Chi and VanLehn, 1991). Good problem solvers will try another strategy if one is not working, while poor problem solvers will hold to a strategy long after it has failed. Likewise, good writers will think about how a hypothetical audience might read their work and revise parts that do not convey their meaning (Hayes and Flower, 1986).
There is ample evidence that metacognition develops over the school years; for example, older children are better than younger ones at planning for tasks they are asked to do (Karmiloff-Smith, 1979). Metacognitive skills can also be taught. For example, people can learn mental devices that help