Flynn effect

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The Flynn effect describes the fact that up to the 1990s the results of IQ tests - if no recalibration was carried out - in industrialized countries produced ever higher values, i.e. the measured intelligence increased. This trend was first described for the United States in 1984 by the New Zealand political scientist James R. Flynn and called the Flynn effect in 1994 by Charles Murray and Richard Herrnstein .

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Using test results from 14 industrialized nations, Flynn (1987) showed that the increases in IQ scores were between 5 and 25 points per generation. In further studies, Flynn found that the increase in test scores over time was primarily seen in non-verbal, culturally reduced tests. Flynn concluded that intelligence in the narrow IQ sense had increased in the first three quarters of the 20th century, but was skeptical about an increase in intelligence in the broader sense (he didn't think people were significantly more intelligent than theirs Ancestors).

Possible causes

In explanatory models, the Flynn effect is largely attributed to the improvement in environmental conditions, e.g. B. Education, nutrition, health care and mass media (see also: Euthenics ). Mingroni (2004, 2007), however, suspects genetic factors as the cause. A heterosis effect is also conceivable due to the mixing of previously separated subpopulations resulting from urbanization and increased mobility. There is no scientific consensus on the suspected causes of the Flynn effect.

Gender difference

According to Flynn, the effect seems to have had different effects on the sexes. In the 100-year history of the IQ test, the results of women were up to 5 points behind those of men, but have converged in recent years:

"In the last 100 years the IQ scores of both men and women have risen, but women's have risen faster."

"Over the past 100 years the IQ values ​​of men and women have risen, but those of women have risen faster."

- James R. Flynn

In 2012, the test results of women - at least in certain countries - were for the first time just above the results of men (IQ values ​​between 100.5 and 101.5 in Ravens matrix test in the four countries New Zealand, South Africa (white population), Estonia and Argentina: In Australia, on the other hand, the female IQ was 99.5 - in each case a male IQ normalized to 100).

Development after 1984

Sundet and colleagues (2004) studied the test results of Norwegian conscripts tested between the mid-1950s and 2002. While a strong increase was recorded until the beginning of the 1970s, this then decreased until it disappeared in the mid-1990s. The average increase was mainly caused by a decrease in low test scores. The authors conclude that the Flynn effect may have come to an end in Norway. According to Sundet and colleagues (2008), this end of the Flynn effect in Norway is not easy to explain, but it is possible that a higher proportion of immigrants (who on average achieve poorer results in the Netherlands) among the conscripts is responsible. Other researchers attributed this to the advent of commercial television . After 10 years of exposure to private television, the IQ drops by 1.8 points.

Using test results from 500,000 young Danish men between 1959 and 2004, Teasdale and Owen (2005) showed that IQ peaked in the late 1990s, from which it has since fallen back to pre-1991 levels. One possible explanation for the declining IQ scores in Denmark, according to Teasdale and Owen, is a decline in the proportion of 16 to 18 year olds in secondary schools. Since no causality can be derived from correlation, other explanations are also possible. Another factor could be immigration . Dutch data show that children of immigrants do worse on intelligence tests than ethnic Dutch children.

A meta-study from 2015 showed that the global IQ, determined from 219 studies from 31 countries in the period from 1909 to 2013, rose by a full 30 points.

In addition to these results from Norway and Denmark, studies from Australia (2005) and the United Kingdom (2007) also found stagnation or a decline in the measured IQ. According to Lynn and Harvey, other industrialized countries would follow suit as soon as environmental improvements can no longer compensate for the dysgenic effects due to the negative correlation between intelligence and fertility .

Flynn, on the other hand, in his 2012 book Are We Getting Smarter? found another increase in intelligence. Germany recorded an increase of 0.35 points per year, Brazil and Turkey almost twice as much. However, the type of intelligence has changed. Above all, the visual and logical thinking of the children is improved, while the vocabulary is only marginally improved.

literature

Web links

Individual evidence

  1. ^ A b Earl Hunt : Human Intelligence . Cambridge University Press, 2010, ISBN 0521707811 . P. 265
  2. ↑ JR Flynn: Massive IQ gains in 14 nations: What IQ tests really measure. PDF; 2.3 MB. In: Psychological Bulletin. Volume 101 (2), 1987. pp. 171-191.
  3. ^ A b Jon Martin Sundet, Ingrid Borren, Kristian Tambs: The Flynn effect is partly caused by changing fertility patterns. PDF; 392 kB. In: Intelligence. Volume 36, 2008. pp. 183-191.
  4. ^ A b TW Teasdale, DR Owen: A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse. PDF; 111 kB. In: Personality and Individual Differences. Volume 39, 2005. pp. 837-843
  5. ^ JR Flynn: The mean IQ of Americans: Massive gains 1932 to 1978. In: Psychological Bulletin. 1984
  6. ↑ JR Flynn: Massive IQ gains in 14 nations: What IQ tests really measure. In: Psychological Bulletin. 1987
  7. ↑ Michael A. Mingroni: The secular rise in IQ: Giving heterosis a closer look. In: Intelligence. Volume 32 (1), 2004. pp. 65-83.
  8. ↑ Michael A. Mingroni: Resolving the IQ Paradox: Heterosis as a Cause of the Flynn Effect and Other Trends. PDF; 339 kB. In: Psychological Review . Volume 114 (3), 2007. pp. 806-829.
  9. ↑ M. Amelang et al .: Differential Psychology and Personality Research. Kohlhammer, Stuttgart 2006, p. 199
  10. ^ Harriet Cooke: IQ tests: women score higher than men. The Telegraph, July 15, 2012, accessed May 7, 2013 .
  11. ^ Scott Barry Kaufman: Men, Women, and IQ: Setting the Record Straight. Psychology Today , July 20, 2012, accessed May 7, 2013 .
  12. ↑ JM Sundet, DG Barlaug, TM Torjussen: The end of the Flynn effect? A study of secular trends in mean intelligence test scores of Norwegian conscripts during half a century. PDF; 213 kB. In: Intelligence. Volume 32, 2004. pp. 349-362
  13. ↑ J. te Nijenhuis, M.-J. de Jong, A. Evers, H. Van der Flier: Are cognitive differences between immigrants and majority groups diminishing? In: European Journal of Personality. Volume 18, 2004, pp. 405-434.
  14. ↑ Jonathan Rothwell: You Are What You Watch? The Social Effects of TV . In: The New York Times . July 25, 2019, ISSN  0362-4331 ( nytimes.com [accessed August 1, 2019]).
  15. ↑ Thomas W. Teasdale, David R. Owen: Secular declines in cognitive test scores: A reversal of the Flynn Effect. PDF; 252 kB. In: Intelligence. Volume 36, 2008. pp. 121-126.
  16. ↑ Jakob Pietschnig, Martin Voracek: One Century of Global IQ Gains: A Formal Meta-Analysis of the Flynn Effect (1909-2010) . In: SSRN Electronic Journal . tape 10 , January 1, 2013, doi : 10.2139 / ssrn.2404239 ( researchgate.net [accessed February 21, 2018]).
  17. ^ Richard Lynn, John Harvey: The decline of the world's IQ. PDF; 309 kB. In: Intelligence. Volume 36, 2008. pp. 112-120
  18. ↑ Generation of the super brain. In: Der Spiegel 37/2012, pages 128-129