"When it comes to religion, there are a lot of things that Americans are unfamiliar with. That's the main takeaway," says Greg Smith, a senior researcher at the think tank and one of the main authors of the survey.
Smith has a theory about why atheists did so well on the quiz - they have thought more about religion than most people.
"Very few people say that they were raised as atheists and agnostics," he explains.
About three out of four were raised as Christians, he says.
"They were raised in a faith and have made a decision to identify themselves with groups that tend to be fairly unpopular," atheists and agnostics, he says.
Check out the article here: http://religion.blogs.cnn.com/2010/09/28/dont-know-much-about-religion-youre-not-alone-study-finds/?hpt=C1
And in case you were curious, I'm atheist, raised Southern Baptist.