Religion is the big factor here. “Regions of the country that are deeply religious are more generous than those that are not,” the Chronicle said.

Red states give much more than blue states. The eight states where residents gave the highest share of their income to charity went for John McCain in 2008, according to the Chronicle. The seven-lowest ranking states supported Barack Obama.

The study will no doubt prompt controversy from both sides of the political aisle, with liberals saying the wealthy don’t give (and therefore should be taxed more), while conservatives will say they give more than left-leaning states.

The study also feeds into the new thread of research that argues that the wealthy are meaner and more selfish than the non-rich. The Chronicle of Philanthropy study suggests that wealthy people who live in mixed-income areas give more and are more empathetic than those who live in exclusively wealthy enclaves.

There is one important fact that is missing from all of these studies. High-income earners still account for the largest share of giving. In 2006 taxpayers with incomes over $100,000 made more than half of all donations, according to The Economist.

Of course, they also make the lion’s share of the country's income.

But when it comes to looking for the big money in philanthropy, the wealthy and high-earners should still be the largest target group for charities.

Do you think the rich are less charitable than the non-rich?





-By CNBC's Robert Frank

Follow Robert Frank on Twitter: @robtfrank