Migration’s national‑IQ externalities

Low‑skilled immigration can produce negative social externalities — via changes in average cognitive‑related traits that correlate with crime, cooperation, and civic capacity — that may swamp modest labor‑market complementarities economists emphasize. This reframes immigration policy from a pure GDP/wage calculation to a question about long‑run social capital and public goods provision. — If true, policy debates should weigh population composition effects on social trust, crime, and institutional demand alongside standard economic models when setting immigration scale and skill priorities.