An 1840 census error seeded the false claim that freedom caused Black insanity

Evidence

One of the first major scientific controversies in the United States began with what seemed like a simple observation. Harvard-trained, antislavery psychiatrist Edward Jarvis reviewed data from the 1840 US Census and found that northern free Blacks were about ten times more likely to have been classified as insane than enslaved southern Blacks. On September 21, 1842, he published his findings in the New England Journal of Medicine, which was and remains the nation’s leading medical journal. Slavery must have had “a wonderful influence upon the development of the moral faculties and the intellectual powers” of Black people, Jarvis ascertained. — Ibram X. Kendi, Stamped from the Beginning, 480

Categorization

• QUESTION: Jarvis was an antislavery psychiatrist whose finding backed slavery — worth chasing how an abolitionist rationalized a pro-slavery data read.
• SEED: Article angle: an antislavery scientist producing science that justified slavery — how the data, not ideology, drove the conclusion, complicating the ignorance-to-hate model.