New from Pew Research Center: The term ‘religiously unaffiliated’ includes atheists, agnostics and those who describe their religion as ‘nothing in particular.’ But there are differences among them. For example, atheists and agnostics know more about religion than those in the ‘nothing in particular’ group, according to a recent Pew Research Center survey designed to measure the U.S. public’s knowledge about a wide range of religious topics. Fact Tank takes a closer look.