If Christians were to realize just how many atheists there really are, their conceptions of atheists would be challenged, since so many of their neighbors -- and often dear friends -- are secretly atheist. The direct evidence that their friends, neighbors, trusted employees, and beloved family members are not immoral or untrustworthy might well soften their opinions.
Across four different studies, this hypothesis proved spectacularly true. After controlling for relevant confounding variables, the evidence was clear. When prejudiced religious people come to believe that atheists are very common, their opinion of atheists shifts away from distrust towards more acceptance.
MORE: http://www.examiner.com/article/science-says-atheists-should-come-out-of-the-closet-for-their-own-good