James Flynn

Across 30 countries and 100 years, average IQ scores rise about three points every decade — which means, if IQ is fixed, our grandparents were borderline cognitively impaired, and they weren't.

James Flynn was a political philosopher at the University of Otago who noticed in the early 1980s that IQ test publishers were quietly re-norming their tests upward every decade, because raw scores kept drifting up. He gathered data from 30 countries and showed a consistent pattern: average IQ rises ~3 points per decade, with the largest gains on the most "abstract" reasoning subtests (Raven's Progressive Matrices). The result became the Flynn Effect (1984, broader publication 1987). The implication is fatal to any fixed-trait reading of IQ: whatever IQ is measuring, populations get better at it across generations. Better nutrition, more schooling, more exposure to abstract symbol-manipulation in everyday life — Flynn argued the modern environment trains the kind of cognition the tests reward. The arithmetic is striking: an average teenager in 2026 would score in roughly the top 2% against a sample drawn from 1916. Either humanity grew radically smarter in 100 years, or the test was always measuring something more trainable than its inventors believed. Flynn himself thought it was the latter — and that the gains will eventually plateau as the cognitive demands of modern life saturate. The number that defines the right tail of the bell curve moves.