What is the Flynn effect and how does it affect IQ?

David Holt
What is the Flynn effect and how does it affect IQ?

The Flynn effect describes why the general population's IQ scores change by increasing over time. And it is a fact that the results in the IQ tests have been improving without ceasing since the beginning of the 20th century..


  • The origin of the Flynn Effect
    • Origin of the IQ data studied for the Flynn Effect
  • What are the possible causes of the Flynn effect?
    • Flynn's hypothesis
  • Hypothesis 1: Education
  • Hypothesis 2: Social changes
  • Hypothesis 3: Better nutrition
    • References

The origin of the Flynn Effect

In the eighties James R. Flynn, a researcher at the University of Otago in New Zealand, discovered a curious phenomenon that happened with the calculation of the population IQ.

Flynn examined the intelligence tests of more than two dozen countries (countries for which data existed) and found that the scores increased at the rate of 0.3 points per decade..

This interesting phenomenon, now known as the Flynn effect, has been confirmed after almost 30 years of monitoring in many countries. And the scores continue to rise.

Research shows that countries have experienced generation gains of between 5 and 25 points. The biggest gains appear to occur in tests that measure fluid intelligence rather than crystallized intelligence..

Origin of the IQ data studied for the Flynn Effect

The countries for which data have been collected to investigate the increase in IQ scores over time are: Australia, Austria, Germany, Belgium, Brazil, Great Britain, Canada, China, Denmark, United States, France, Israel , Japan, Netherlands, New Zealand, Northern Ireland, Norway, Sweden and Switzerland.

What are the possible causes of the Flynn effect?

What Do IQ Tests Really Measure? How much do you value learning versus pure intelligence or any other factor that correlates with intelligence? The answers to these questions are still being researched by academics around the world..

Flynn's hypothesis

According to Flynn, the hypothesis that best fits the results is that IQ tests do not measure real intelligence, but a part of it, the most academic or that we acquire with practice and learning.

Based on the presence of the effect in non-verbal tests such as Raven's matrices (The Raven's Test consists of finding the missing piece in a series of figures that are shown). Flynn believes that the increase is actually an increase in abstract problem solving rather than general intelligence. Flynn favors environmental explanations over rising test scores.

Hypothesis 1: Education

In many countries, the general education level of the younger generations is increasing significantly. People spend a great deal of time learning and being tested in formal educational settings. This is why in many cases, IQ gains are highly correlated with the increase in the last years of formal education. On the contrary, some scholars point out the also increase in tests to measure IQ, free of academic parameters, are evidence against the educational hypothesis.

Hypothesis 2: Social changes

Other scholars suggested that social changes, especially in terms of control of the execution of tasks within a fixed time, could be a cause of IQ gains. The idea behind this hypothesis is that people in our society have learned to work better within a limited time frame. This social trend allows later generations to score better on scheduled tests, because they make smart guesses and don't waste time trying to get every item on the test correct. Although this hypothesis seemed promising, there has been research that contradicts its fundamental assumptions..

Hypothesis 3: Better nutrition

It has also been hypothesized that IQ gains are the result of better global nutrition. This hypothesis is based on the fact that better nourished brains allow subjects to perform better on intelligence quotient tests, as well as in daily activities. The experimental data attempting to test this theory is also mixed, leading to the belief that nutrition, while a possible contributing cause, cannot fully explain the massive gains in IQ measured around the world..

All this leads us to think that it is most likely that the three hypotheses have their part of truth, and the conjunction of all of them is what makes us achieve this progressive increase in intelligence test scores in the population. So let's take advantage of this advantage for good and try to make the Earth a better world..


  • Deary, I. J. (2001). Intelligence: A very short introduction. Oxford: Oxford University Press.
  • An accessible and colorful analysis of a wide range of intelligence topics. The chapter on the Flynn Effect (Chapter 6) is among the best in the book.
  • Flynn, J. R. (1984). The mean IQ of Americans: Massive gains 1932 to 1978. Psychological Bulletin, 95, 29-51.
  • Flynn, J. R. (1985). Wechsler intelligence tests: Do we really have a criterion of mental retardation? American Journal of Mental Deficiency, 90, 236-244.
  • Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101,171-191.
  • Flynn, J. R. (1991). Asian Americans: Achievement beyond IQ. Hillsdale, NJ: Erlbaum.

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