What’s going on? A new study, released Saturday, suggests that the gradual secularization of the nation has not eliminated the perceived social desirability of going to church, and the result is that Americans exaggerate their religious behavior. That exaggeration is more pronounced among some groups — Catholics, mainline Protestants and, strikingly, the unaffiliated, meaning that even people willing to say they don’t belong to a religious tradition still feel compelled to exaggerate their attendance at worship services.

The study, by the Public Religion Research Institute, used an intriguing method to try to measure exaggeration: It asked the same set of questions in telephone interviews, and in an online survey, and compared the results. Researchers say that online surveys, with their lack of human questioners, significantly reduce “social desirability bias” in polling — the tendency of people to exaggerate behaviors that they think will impress others. In this study, the group that took the online surveys reported much lower levels of worship attendance than those interviewed by telephone.