This Is Only a Test? Long-Run Impacts of Prenatal Exposure to Radioactive Fallout

Research increasingly shows that differences in endowments at birth need not be genetic but instead are influenced by environmental factors while the fetus is in the womb. In addition, these differences may persist well beyond childhood. In this paper, we study one such environmental factor ? exposure to radiation?that affects individuals across the socio-economic spectrum. We use variation in radioactive exposure throughout Norway in the 1950s and early 60s, resulting from the abundance of nuclear weapon testing during that time period, to examine the effect of nuclear exposure in utero on outcomes such as IQ scores, education, earnings, and adult height. At this time, there was very little awareness in Norway about nuclear testing so our estimates are likely to be unaffected by avoidance behavior or stress effects. We find that exposure to nuclear radiation, even in low doses, leads to a decline in IQ scores of men aged 18. Moreover, radiation exposure leads to declines in education attainment, high school completion, and earnings among men and women. These results are robust to the choice of specification and the inclusion of sibling fixed effects.