Black-White Gap in IQ Scores Closing, Study Finds

The gap in IQ scores between whites and African-Americans has narrowed by at least a quarter since 1972, a pair of researchers contend in a new paper that attempts to skewer the argument that intelligence is a mostly inherited trait.

Researchers William T. Dickens and James R. Flynn analyzed 30 years of test-score data from four commonly used intelligence tests. From 1972 to 2002, they found, IQ scores rose for all groups, but scores for blacks rose faster. They gained 5 to 6 IQ score points more than whites did—an improvement the researchers characterize as considerable.

"We believe there's been a real change," said Mr. Dickens, a senior fellow in economic studies at the Brookings Institution, a Washington-based think tank. "And we suspect that it has something to do with improving conditions, at least for black youth and young adults." His co-author, Mr. Flynn, a professor of political studies at the University of Otago in Dunedin, New Zealand, is best known for having documented the "Flynn effect," the worldwide rise in IQ scores...