The article you linked to is paywalled, which offers the abstract, Infectious disease was the best predictor of average IQ. But the study appears to conflate in

The article you linked to is paywalled, which offers the abstract, Infectious disease was the best predictor of average IQ. But the study appears to conflate infectious disease with parasite and offers no way to look at the data they used. Correlation is not Causation: You might want to look at the prevalence of infectious diseases by race according to the CDC. https://www.cdc.gov/nchhstp/healthdisparities/africanamericans.html https://www.cdc.gov/nchhstp/healthdisparities/africanamerica... Edit: Insert Numbers; Black People make up 14% of US population and 45% of the total of HIV/Aids 62% of women with HIV/Aids 55% of Gonorrhea Chalmydia: Black Women 5.2x more likely and Black men 7.3 times more likely as white people 38% of Syphilis cases Black Men and Women over 5 times as likely as white people 37% of TB cases Black people, and 87% of all reported TB cases occurred in racial and ethnic minorities