TIL that IQ test scores globally rose significantly from their introduction until the mid-1990s, after which they likely have started to decline - eviltoast

To clear up confusion, IQ tests are standardized so that the mean is always 100, but if a person today take a test from 30 years ago he’ll probably score poorly and if he takes a test from 80 years ago he’ll score great.

No one knows why the trend started or stopped.