Black-White inequality declined during much of the 20th century as measured by wages and intergenerational mobility. Scholars have attributed this to a variety of reasons, most notably Black migration and increases in Black people's education levels. In a new study, researchers investigated the long-term impact of the boll weevil, an agricultural pest that destroys cotton crops, which invaded the South in the early 20th century and spurred significant economic changes. They found that this agricultural shock brought about long-term advantages for Black sons born after the boll weevil appeared.
The study, by researchers at Carnegie Mellon University and Marquette University, appears in The Economic Journal.
"Our work sheds new light on the improvement in the economic status of Black men in the first half of the 20th century," says Karen Clay, professor of economics and public policy at Carnegie Mellon's Heinz College, who coauthored the study. "Most research has focused on education and migration to the North; we looked at the factors that led to improvement by showing that a large agricultural shock, the boll weevil, generated long-term benefits for Black sons born after its arrival."
Starting in 1892, the boll weevil began to spread gradually through the cotton-growing region of the United States, infesting all such areas by 1922. As a result, total cotton production fell as much as 50%, affecting nearly a third of the U.S. population and 75% of the Black population, as many farm owners ended or changed tenancy contracts and many households migrated from their counties.
In this study, researchers used cross-Census links from the Census Tree, the largest database of record ties among historical U.S. censuses, with more than 700 million links for U.S. residents between 1850 and 1940. They examined changes in earnings, occupations, family makeup, and residences, among other measures, for Black males born before and after the boll weevil's appearance.
The pest's arrival benefited Black sons in the long term, as reflected in two 1940 measures of income—wages and attributed income—and did not harm White sons, and these differential gains decreased inequality, the study found. In a variety of ways, early life conditions may have improved for Black sons relative to White sons. More specifically:
- Compared to White sons, Black sons born after the agricultural shock experienced relative increases in wages of 11% and relative increases in imputed incomes of 5%. These gains were not driven by migration out of the South; Black sons who remained in the South also had increased wages and incomes.
- These differential gains pushed down inequality as measured by wages and income rank. The gains in Black sons' wages and imputed incomes were substantial, accounting for 6% to 15% of the Black-White wage gap in 1940. Estimates from analyses of intergenerational mobility show that being born after the boll weevil appeared boosted Black sons' imputed income rank by 1 and had a negative but insignificant effect on White sons' imputed income rank, representing a 12% rise in average income rank for Black sons.
- These surprising improvements appear to have occurred through a range of mechanisms related to the boll weevil. Black sons may have benefited from their fathers' migration and occupational upgrading; improvements in nutrition and schooling; increases in household resources available to sons, including reductions in the number of children in the household; and reductions in racial violence.
"Our study provides new evidence of the effect of the boll weevil on Black-White wages and intergenerational mobility, as well as on changes in Black fathers' labor market conditions relative to White fathers and the impact this had on their sons," explains Ethan J. Schmick, assistant professor of economics at Marquette University, who coauthored the study. "Our work also contributes new evidence on Black individuals' and White individuals' early life conditions during an important and understudied historical period, highlighting the role of a range of market mechanisms in mitigating shocks."
