The negative Flynn Effect: A systematic literature review

- We conducted a systematic literature review of the negative Flynn effect.
- A negative Flynn effect was reported in 9 studies (comprising 7 countries).
- Immigration, sex ratio, and dysgenic fertility were discussed as possible causes.
- Findings on IQ decline are discussed in light of the literature on IQ increase.

The Flynn Effect (rising performance on intelligence tests in the general population over time) is now an established phenomenon in many developed and less developed countries. Recently, evidence has begun to amass that the Flynn Effect has gone into reverse; the so-called 'Negative Flynn Effect.' In this study, we present a systematic literature review, conducted in order to discover in precisely how many countries this reverse phenomenon has been uncovered. Using strict criteria regarding quality of the sample and the study, we found nine studies reporting negative Flynn Effects in seven countries. We also discuss several possible explanations for the negative Flynn Effect as an attempt to understand its most probable causes.