The end of the Flynn effect?: A study of secular trends in mean intelligence test scores of Norwegian conscripts during half a century

The present paper reports secular trends in the mean scores of a language, mathematics, and a Raven-like test together with a combined general ability (GA) score among Norwegian (male) conscripts tested from the mid 1950s to 2002 (birth cohorts c1935–1984). Secular gains in standing height (indicating improved nutrition and health care) were also investigated. Substantial gains in GA were apparent from the mid 1950s (test years) to the end 1960s–early 1970s, followed by a decreasing gain rate and a complete stop from the mid 1990s. The gains seemed to be mainly caused by decreasing prevalence of low scorers. From the early 1970s, the secular gains in GAwere almost exclusively driven by gains on the Raven-like test. However, even the means on this particular test stopped to increase after the mid to late 1990s. It is concluded that the Flynn effect may have come to an end in Norway. Height gains were strongly correlated with intelligence gains until the cessation of height gains in the conscript cohorts towards the end of the 1980s. Contrary to the intelligence gains, the height gains (conscript cohorts 1969–2002) were most pronounced in the upper half of the distribution. Evidence indicating decreasing intercorrelations between tests is reported. D 2004 Elsevier Inc. All rights reserved.