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Interessant3 #152 | Fertility & IQ, Nat Friedman’s Beliefs, Startup Decks
By Duarte Martins
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August 17, 2025
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327 words
International meta-analysis of the relationship between fertility and intelligence
The study draws on 610 datasets (n ≈ 1.2m) to test whether people with higher or lower intelligence have more children across 65 countries.
Results suggest global IQ is declining by ~1.1 points per decade to 2100, with about one-third of the decline happening within countries.
Patterns differ: strongest negative IQ–fertility link in Latin America, Iran, and Turkey; weakest (near zero) in Scandinavia and Switzerland.
Authors caution that poor data quality in some countries tempers confidence—measurement issues may blur real differences.
National IQ correlates moderately with fertility differentials (r = .51), linking societal development to demographic selection. !
International meta-analysis of the relationship between fertility and intelligence – OpenPsych (PDF)
Nat Friedman - Some Things I Believe
Friedman (former GitHub CEO, now AI investor) sets out a philosophy of speed, ambition, and intellectual independence.
Core stance: technology is humanity’s lever to reshape the universe, and progress depends on moving fast and pursuing big ideas.
He rejects the efficient market hypothesis as misleading, suggesting opportunity lies where consensus fails.
Culture: fewer, sharper teams; empower great individuals; accept mistakes if they yield “uncorrelated excellence.”
A recurring theme is dopamine: true builders derive motivation from improving ideas and creating impact, not external validation.
Some Things I Believe – Nat Friedman
Barney Hussey-Yeo —Sharing Startup Pitch Decks (2016–2022)
The Cleo founder published all his fundraising decks, from a modest £600k seed (2016) to an $80m Series C (2022).
Each deck reflects shifting investor climates: early enthusiasm at EF Demo Day, frictionless pre-emptions for Seed & Series A, and a gruelling Series B.
Series B highlights: even strong growth plus U.S. traction didn’t guarantee easy money- timing and narrative mattered.
His guiding principle across decks: build an AI agent that makes money work for ordinary people - big vision, clearly expressed.
Startup Pitch Decks Thread – X (@Barney_H_Y)