Maths

This is an interesting study but I can't help but think that there must be some other contributing factors, especially since the same result didn't occur for black women or whites.

P.S. I find it amusing that the Brits say "maths."

From the Economist...

Mr Goodman has found that each extra required maths course raised the annual income of black males by 15%. (More reading classes had a negative or no effect on earnings.) More maths also increased the likelihood of young black men going to university and someday having a job requiring quantitative skills. But an advanced degree or better job accounts for only a fraction of the earnings increase.

According to Clancy Blair, a professor of psychology at NYU, the act of performing mathematical calculations improves reasoning, problem-solving skills, behaviour, and the ability to self-regulate. These skills are associated with the pre-frontal cortex part of the brain, which continues to develop into your early 30s. Solving maths problems improves the way your brain functions and, according to Mr Blair, this can translate into an ability to earn more money and form stable relationships.

Curiously, Mr Goodman found that requiring more maths did not have much impact on the income of black women or whites.