The microgenetic method: A direct means for studying cognitive development.

Progress in understanding cognitive developmental change mechanisms requires methods that yield detailed data about particular changes. The microgenetic method is an approach that can yield such data. It involves (a) observations of individual children throughout the period of the change, (b) a high density of observations relative to the rate of change within that period, and (c) intensive trial-by-trial analyses intended to infer the processes that gave rise to the change. This approach can illuminate both qualitative and quantitative aspects of change, indicate the conditions under which changes occur, and yield otherwise unobtainable information about short-lived transition strategies. The cost in time and effort of such studies is often high, but the value of the information about change can more than justify the cost.