- The Flynn effect is the well-documented rise in average IQ scores of about 3 points per decade across the 20th century.
- The reverse Flynn effect is the finding that, since roughly the 1990s-2000s, average test scores have stopped rising and slightly declined in several developed nations.
- No, the data does not show that people are becoming less capable in any deep or genetic sense.
- The most supported explanations are environmental rather than biological.
- Because the strongest evidence comes from within-cohort and within-family registry data, where genetic makeup is held roughly constant.
What is the Flynn effect?
The Flynn effect is the well-documented rise in average IQ scores of about 3 points per decade across the 20th century. Named after researcher James Flynn, it was observed in many countries and is credited to better nutrition, more schooling, smaller families, and a culture that increasingly rewards abstract, scientific reasoning. Because it is so large, IQ tests must be re-normed periodically to keep the average at 100.
What is the reverse Flynn effect?
The reverse Flynn effect is the finding that, since roughly the 1990s-2000s, average test scores have stopped rising and slightly declined in several developed nations. Studies from Norway, Finland, Denmark, France, and the UK have reported small downward shifts of a few points across recent birth cohorts. The dips are modest and country-specific, not a worldwide collapse in intelligence.
Are we actually getting dumber?
No, the data does not show that people are becoming less capable in any deep or genetic sense. What changed are average scores on specific standardized tests, which are sensitive to education styles, test-taking familiarity, reading habits, and attention. Some skills (like rapid visual-digital processing) may even be improving while the particular abilities these tests measure shift, so 'dumber' is the wrong word for a nuanced, test-bound trend.
What causes the reverse Flynn effect?
The most supported explanations are environmental rather than biological. Candidate factors include changes in school curricula and reading instruction, more fragmented media and screen-based attention, and shifting test motivation. Crucially, Norwegian conscript studies found score declines within the same families across brothers, which argues against genetic or immigration-based explanations and points squarely at environment.
Why isn't this about genetics or any group?
Because the strongest evidence comes from within-cohort and within-family registry data, where genetic makeup is held roughly constant. The Norwegian conscript analyses compared brothers born in different years and still found declines, meaning the change tracks the environment a cohort grew up in, not heredity. Responsible reading of this research never frames it as one group being innately smarter or less able than another.
Flynn and Reverse Flynn Effect: Trends by Era and Region
| Era / region | IQ score trend | Likely driver |
|---|---|---|
| 20th century (global) | Rising about 3 points per decade | Better nutrition, mass education, abstract-thinking demands |
| ~2000s Norway & Finland | Small decline across cohorts | Environmental (within-family registry evidence) |
| Recent UK & France | Small decline reported | Debated environmental factors (education, media, attention) |
| Overall conclusion | Mixed: rise then modest dip | Environmental and reversible, not genetic |
β People also ask
What Is a Good IQ Score?
An IQ of 100 is exactly average; 110-119 is above average, 120 and up puts you in the top 10% (a genuinely 'good' score), and 130+ is considered gifted. IQ is built on a normal distribution with a mean of 100 and a standard deviation of 15, so most people cluster near the middle.
What Is a Good IQ Score? βIQ Percentile Chart: What Percentile Is My IQ?
Your IQ percentile tells you the share of people you scored higher than: an IQ of 100 is the 50th percentile, 115 is about the 84th, 120 is roughly the top 10%, and 130 is roughly the top 2%. The table below maps every major IQ band to its classification, percentile, and share of the population.
IQ Percentile Chart: What Percentile Is My IQ? βAre Online IQ Tests Accurate?
A well-designed online IQ test gives a reliable estimate of your reasoning ability, but it is not a clinical diagnosis β only a proctored test like the WAIS or Stanford-Binet provides that. This test is built on Raven's Progressive Matrices and CHC theory, scored on the standard scale (mean 100, SD 15), with an internal reliability (Cronbach's alpha) of about 0.85-0.92.
Are Online IQ Tests Accurate? βCan You Increase Your IQ?
You can meaningfully sharpen reasoning skills, working memory, and test performance through training and education, but raising your underlying general intelligence (g) substantially and permanently is not well supported β core g is largely heritable. The honest answer is that some gains are real and some popular claims are overstated.
Can You Increase Your IQ? βGenius IQ Level: What Number Counts as Genius?
A 'genius' IQ traditionally starts at 140, while 130 and above is labeled 'very superior' on modern tests. Scores that high are extremely rare, and the famous IQ numbers you see for historical figures are almost always estimates, not measured results.
Genius IQ Level: What Number Counts as Genius? β