Cognitive development: Past, present, and future.

This article summarizes what developmentalists have come to believe about human cognitive development after over a century of study. Topics briefly considered include the child as constructive thinker, invention of new research methods; the diagnosis problem; recent changes in estimates of children's competence; the question of general stages vs. domain-specific developments; the effects of expertise; natural domains and constraints; cognitive development as theory development; synchronisms, sequences, and qualitative changes; mechanisms of development; sociocultural influences; individual differences; practical applications; and suggestions about what develops. The article concludes with some guesses about future directions for the field