title: Three Lessons Learned.
abstract: In this article, I describe varied observations from the past 60 years that motivated three significant changes in the assumptions I held as a young psychologist interested in the development of children. Aspects of these early assumptions penetrate a great deal of current research. The new beliefs are (a) a greater willingness to base concepts on patterns of measurements rather than single independent or dependent variables, (b) learning to include the physical features of the observational setting, including the procedure that generated the evidence, as well as the participants' gender, social class, and cultural background, as part of the concept, and (c) remaining aware of the possibility that the relations among continuous variables can change as a function of brain maturation during the early stages of childhood.
authors.affiliation: Department of Psychology, Harvard University, Cambridge, MA jk@wjh.harvard.edu.
authors.forename: Jerome
authors.initials: J
authors.lastname: Kagan
keywords: child development; scientific methodology