Practice question · Multiple choice
Raw IQ performance has risen substantially across the twentieth century, yet the average IQ score has stayed at exactly 100 the whole time. Why did nobody notice the Flynn effect for decades?
Hints
- What does a score of 100 actually mean? Relative to whom?
- If the yardstick is re-cut every twenty years to keep the average at 100, what would growth look like?
Show the answer
D. Because the tests are periodically restandardised to a mean of 100.
Why
The measure is designed to hide it, 100 is defined as the current population's average, so if everyone improves nothing moves, and restandardisation absorbs the gain each time. Flynn looked where it could not hide: scored against 1940s norms, a 1990s sample averaged well above 100. Three points per decade is far too fast for the gene pool to have changed.
Practise Measuring Intelligence
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