- Cognitive performance markers exhibit stagnant selection patterns in the last 2,000 years.
- The most significant selective pressure on these variants occurred during the period 2,000 to 4,000 years ago.
- Industrialization and modern societal demands show no clear correlation with intensified selection of these specific genetic traits.
Channel: Dwarkesh Patel
Why Humans Stopped Evolving Smarter 2,000 Years Ago - David Reich
This video examines evidence for natural selection acting on genetic variants linked to modern cognitive performance, comparing different historical periods of the last 5,000 years.
Key Takeaways
- Genetic markers associated with today's cognitive performance show no signs of natural selection over the last 2,000 years.
- Strong evidence for selection on these traits occurred primarily between 2,000 and 4,000 years ago.
- The intensity of selection during the Bronze Age reached two standard deviations, significantly higher than subsequent eras.
Talking Points
Analysis
Strategic Significance:
- This research challenges the assumption that modern civilization's complexity acts as a primary engine for current human biological evolution regarding intelligence-related genetic markers.
Who Should Care:
- Anthropologists, evolutionary biologists, and public policy researchers interested in the intersection of genetics, history, and population health.
Contrarian Takeaway:
- Higher environmental demands, such as those found in industrial settings, do not necessarily correlate with measurable natural selection for cognitive performance, suggesting human evolution is not simply reactive to modern societal advancement.
Channel: Dwarkesh Patel