Working Paper: NBER ID: w18987
Authors: Sandra E. Black; Aline Btikofer; Paul J. Devereux; Kjell G. Salvanes
Abstract: 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, as well as whether these effects persist into the next generation. We find that exposure to low-dose nuclear radiation, specifically during months 3 and 4 in utero, 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. We are also able to examine whether these effects persist across a second generation. Importantly, we find that the children of persons affected in utero also have lower cognitive scores, suggesting a persistent intergenerational effect of the shock to endowments. Given the lack of awareness about nuclear testing in Norway at this time, our estimates are likely to be unaffected by avoidance behavior or stress effects. These results are robust to the choice of specification and the inclusion of sibling fixed effects.
Keywords: Prenatal Exposure; Radioactive Fallout; Cognitive Outcomes; Intergenerational Effects
JEL Codes: I20; J01; J3
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Prenatal exposure to nuclear fallout during months 3 and 4 in utero (J13) | decline in IQ scores for men aged 18 (J11) |
| Prenatal exposure to nuclear fallout during months 3 and 4 in utero (J13) | decline in IQ scores for men aged 18 due to air exposure (I12) |
| Prenatal exposure to nuclear fallout (J13) | decrease in educational attainment for men (I24) |
| Prenatal exposure to nuclear fallout (J13) | decrease in educational attainment for women (I24) |
| Prenatal exposure to nuclear fallout (J13) | lower earnings at age 35 for both genders (J31) |
| Prenatal exposure to nuclear fallout (J13) | lower cognitive scores in children of individuals exposed in utero (I12) |