Why Wasn't Intelligence 'Maxed Out' Before the Bronze Age? - David Reich

Why It Matters

This reframes population cognitive differences as shaped by shifting cultural selection pressures rather than fixed biological ceilings, with implications for how we interpret genetic and IQ variation across time and populations. It highlights that modern education and social values can drive rapid evolutionary change in traits deemed advantageous.

Summary

Geneticist David Reich argues that intelligence was not "maxed out" before the Bronze Age because natural selection favors traits that are adaptive in specific cultural and environmental contexts, and the modern premium on IQ and formal schooling is historically atypical. He notes large predicted differences among ancient populations and emphasizes that selection can shift trait means rapidly when those traits are valued. Historically, societies prioritized attributes like strength, courage, religiosity or beauty rather than abstract cognitive test performance. Thus, the recent elevation of intelligence as a key fitness-related trait is a product of modern cultural evolution, not long-standing biological inevitability.