Ragnar Frisch Centre for Economic Research, 0349 Oslo, Norway.
Ragnar Frisch Centre for Economic Research, 0349 Oslo, Norway
Proc Natl Acad Sci U S A. 2018 Jun 26;115(26):6674-6678. doi: 10.1073/pnas.1718793115. Epub 2018 Jun 11.
Population intelligence quotients increased throughout the 20th century-a phenomenon known as the Flynn effect-although recent years have seen a slowdown or reversal of this trend in several countries. To distinguish between the large set of proposed explanations, we categorize hypothesized causal factors by whether they accommodate the existence of within-family Flynn effects. Using administrative register data and cognitive ability scores from military conscription data covering three decades of Norwegian birth cohorts (1962-1991), we show that the observed Flynn effect, its turning point, and subsequent decline can all be fully recovered from within-family variation. The analysis controls for all factors shared by siblings and finds no evidence for prominent causal hypotheses of the decline implicating genes and environmental factors that vary between, but not within, families.
人口智商指数在整个 20 世纪都有所增加——这种现象被称为弗林效应（Flynn effect）——尽管近年来，在几个国家，这种趋势已经放缓或出现逆转。为了区分大量提出的解释，我们根据假设的因果因素是否能容纳家庭内弗林效应的存在来对其进行分类。利用涵盖挪威三个出生队列三十年的行政登记数据和兵役数据中的认知能力分数（1962-1991 年），我们表明，观察到的弗林效应、其转折点以及随后的下降都可以完全从家庭内的变异中恢复。该分析控制了兄弟姐妹之间共有的所有因素，并且没有证据表明基因和环境因素的显著因果假设，这些因素在家庭之间而不是家庭内部存在差异。
