Question
Are people getting smarter?
Short answer
On IQ tests, yes, for most of the 20th century. Average raw performance rose by about 3 points per decade in the US, and a 2015 meta-analysis of 271 samples estimated about 2.8 points per decade worldwide. The gains have slowed, and some countries show a reversal in recent birth cohorts.
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The Flynn effect
When researchers gave old tests to new generations, the new generations scored higher. James Flynn documented the rise in 1984 at about 3 points per decade in the US. A 2015 meta-analysis pooled 271 samples, about 4 million people in 31 countries tested between 1909 and 2013, and estimated about 2.8 points per decade (Pietschnig & Voracek, 2015). The pattern is known as the Flynn effect.
Why the average still reads 100
IQ is scaled to a mean of 100 for the reference sample a test was normed on (Wikipedia: Intelligence quotient). When publishers restandardize a test, the bar moves up and the average resets. Someone scoring 100 on an old edition could score lower on a new one with the same raw performance. That is the reason tests are renormed.
Try one · Pattern Recognition
Which tile comes next?
Tap the option you think is right, or show the answer.
Show the answer
The missing tile shows four outlined crosses (option 4).
How to solve it
- Compare neighboring tiles and name what changes each time.
- From tile to tile, one more cross is added.
- The fill cycles outline, hatched and solid, then starts again.
- Everything else stays the same from tile to tile.
- The last tile shows three solid crosses. Apply each change once more.
- So the missing tile shows four outlined crosses.
That was 1 puzzle. The full test has 25.
Slowing and reversal
The same 2015 meta-analysis found the gains slowing in recent decades (Pietschnig & Voracek, 2015). In Norway, conscript test data show scores declining for cohorts born after about 1975 (Bratsberg & Rogeberg, 2018). See is the average IQ falling for what that study can and cannot tell us.
Smarter, or better at tests?
Higher scores on the same test are a real change in performance. Whether they mean people are broadly more intelligent is a harder question. The gains arrived too fast to be genetic, which points to changes in the environment such as schooling and everyday familiarity with abstract problems, and a 2015 meta-analysis concluded that factors linked to life history speed, together with social multiplier effects and economic prosperity, best explain the pattern (Pietschnig & Voracek, 2015), though the debate continues. For a definition of the thing being measured, see what intelligence is.
Sources
- Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains. Perspectives on Psychological Science, 10(3), 282-306. doi.org/10.1177/1745691615577701
- Bratsberg, B., & Rogeberg, O. (2018). Proceedings of the National Academy of Sciences, 115(26), 6674-6678. doi.org/10.1073/pnas.1718793115
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient