All I know

Flynn effect

2 min read

Measured IQ has risen over the past century, at rate rate of about 3 points per decade.12 Countries where the average IQ is 100 today had an IQ of 75 a century ago.

The most likely causes are:

  • Increase of intelligence thanks to better education, better nutrition, less violence
  • Changes in measurement

But the Flynn effect is not on General intelligence: g-loaded items are less affected by the Flynn effect.3 This means that the Flynn effect and cognitive differences between countries have different causes, otherwise they would have similar loadings.

The Flynn effect seems to have stalled in developed countries, with some observed but disputed cases of reversal.45

Footnotes

  1. Pietschnig & Voracek (2015), One century of global IQ gains: a formal meta-analysis of the Flynn effect (1909-2013) ↩

  2. Trahan et al. (2014), The Flynn effect: a meta-analysis ↩

  3. te Nijenhuis & van der Flier (2013), Is the Flynn effect on g? The first author is known to have racist ideas and the study cites Rushton and Jensen, but the results are valid if we trust MCV. ↩

  4. Teasdale & Owen (2005), A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse ↩

  5. Pietschnig & Gittler (2015), A reversal of the Flynn effect for spatial perception in German-speaking countries: Evidence from a cross-temporal IRT-based meta-analysis (1977–2014) ↩

Graph View