Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Using a new nationally representative dataset, we find minor differences in test outcomes between black and white infants that disappear with a limited set of controls. However, relative to whites, all other races lose substantial ground by age two. Combining our estimates with results in prior literature, we show that a simple model with assortative mating fits our data well, implying that differences in children's environments between racial groups can fully explain gaps in intelligence. If parental ability influences a child's test scores both genetically and through environment, then our findings are less informative and can be reconciled with a wide range of racial differences in inherited intelligence.