Stability in cognition across early childhood. A developmental cascade.

Children confront the formidable task of assimilating information in the environment and accommodating their cognitive structures to that information. Developmental science is concerned equally with two distinctive features of these processes: children's group mean level of performance through time and the standing of individual children through time. Prevailing opinion since the inception of the mental-measurement movement has been that individual development is unstable-that individual children change unpredictably in their abilities. We report results of a large-scale controlled, multivariate, prospective, microgenetic, 4-year longitudinal study that reveals a statistically significant cascade of species-typical cognitive abilities from infancy to childhood. Infancy is a recognizable starting point of life; we find that to a small but significant degree, infancy also represents a setting point in the life of the individual.