Long-run exposure to low-dose radiation reduces cognitive performance

Abstract

This paper examines the effect of long-run exposure to low-dose radiation on cognitive performance. We focus on the fallout from the Chernobyl accident, which increased the level of ground radiation in large parts of Europe. To identify a causal effect, we exploit unexpected rainfall patterns in a critical time window after the disaster as well as the trajectory of the radioactive plume, which determine local fallout but have no plausible direct effect on test scores. Based on geo-coded survey data from Germany, we show that people exposed to higher radiation perform significantly worse in standardized cognitive tests 25 years later. An increase in initial exposure by one standard deviation reduces cognitive test scores by around 5% of a standard deviation.