Flynn Effect: Rising Intelligence Scores

Flynn effect is the term commonly used to denote the observed increase in scores on IQ tests over time—for example, from one generation to the next. The Flynn effect can be understood as a birth-date effect in that average IQ rises with each increment in year of birth. The phenomenon is named for the New Zealand political scientist James R. Flynn, who described and quantified the rising scores in a series of publications beginning in the 1980s. The term Flynn effect was applied to the phenomenon by Richard J. Herrnstein and Charles Murray in their 1994 book, The Bell Curve. This entry begins by explaining the Flynn effect in terms of the conventions of IQ measurement. Then it describes the scope of the Flynn effect with respect to time and geography. It then specifies the evidence that led to discovery of the rising scores and describes some other data that have been used to characterize the Flynn effect. Then putative causes of the rising scores are considered along with theoretical and practical implications of the IQ increase. The entry ends with a brief note about the future course of IQ changes.