Flynn Effect

A boy in a blue shirt writes a math equation on a large blackboard.The Flynn Effect is the tendency of IQ scores to change over time, and specifically, the apparent increase in intelligence in the general population evidenced by a steady increase in IQ scores. It was first noticed by James Flynn.

What is the Flynn Effect?
Average IQ scores have been steadily increasing every generation. IQ scores are not absolute numbers, but rather, comparisons with the general population. Thus, an IQ score of 100 is always average and always indicates getting about the same number of questions right as the rest of the population.

However, IQ test creators frequently revisit and re-code IQ tests to establish criteria for assigning a person an IQ. Each generation of IQ tests becomes more challenging and is graded more harshly than the last because the general intelligence and knowledge of the population as a whole seems to be increasing. Each generation, when given the previous generation’s IQ test, tends to score substantially higher on the test than the previous generation did.

What Does the Flynn Effect Mean?
The Flynn Effect tends to undermine claims that IQ is absolute, that intelligence is innate, and that IQ tests test for an absolute quality. A number of factors may explain the apparent increase in human intelligence, including:

  • More access to education – More people go to school with each generation, and people tend to stay in school longer.
  • More exposure – Two generations ago, the basic spatial reasoning tasks required to play a video game might have been extremely challenging, but now this knowledge is often commonplace.
  • Test bias – The exam might test knowledge that is learned rather than knowledge that is innate, and might test knowledge that is culturally valued. Thus, cultures will progressively get better at their own IQ tests.
  • Better overall health and nutrition, better prenatal care, and better services for people with disabilities and low IQ could decrease the occurrence of intellectual disabilities.

Flynn’s hypothesis was that IQ tests can’t measure intelligence directly, but instead only measure traits that are somewhat correlated with intelligence.


  1. Human intelligence: The Flynn effect. (n.d.). Indiana University. Retrieved from

Last Updated: 01-17-2018

  • Leave a Comment
  • zelda m.

    June 12th, 2018 at 6:18 AM

    Speech therapist with continuing interest in all aspects of therapy, psychological, physical and emotional

  • Kahsu I.

    April 6th, 2019 at 7:08 AM

    how can igot the flynn case studies

  • SaiSree

    January 26th, 2022 at 4:29 AM

    You will get them in Google Scholar.

  • A.

    May 30th, 2023 at 10:02 PM

    What a good study, I have to study this for psych :o

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