More Intelligence, Less Money?

Robin Hanson linked to this old post, which gives a startling quote:

Here is the shocking conclusion: in the recent years of the GSS (1991 to 2004), for people whose highest level of educational attainment is a bachelor’s degree, there is a negative correlation between intelligence and income. In the 1998 to 2004 data, each point higher on the Wordsum test causes a $1,200 decrease in income.

Didn't have the patience to dig deeply, but part of the answer is in the "bachelor's degree" bit--if you're smart enough to get a graduate degree, then your intelligence is rewarded.