For the strong selection coefficients (roughly 0.5-1% or more) found in this study, natural selection operates effectively whether a population is 1,000 or many millions; what actually limits how fast such selection can produce large trait shifts is elapsed time, not population size.

Reich argues that once selection coefficients are as strong as those found in the Bronze Age data (~0.5-1%), population size stops mattering — even a population of 1,000-10,000 people is plenty large for selection to work, so the real constraint on rapid evolutionary change is simply time elapsed. ✦ AI generated

David Reich · Dwarkesh Podcast · 2026-05-08 · original ↗

We’re talking about strong, measurable selection coefficients on the order of half a percent or more in this study. All of those are going to work in small populations or large populations. It’s not going to be affected by the population size.

verbatim transcript · starts at 57:21