Raise your hand if you go to church.

OK — some of you are lying.

That's what sociology professor Philip Brenner discovered in 2011 when he published research showing that Americans "exaggerate their frequency of attendance" at weekly worship services.

Brenner followed up last year with new research documenting that Christians are not the only people to tend toward overreporting. This time, he expanded his research beyond traditionally Christian, Western democracies and focused on three predominantly Muslim countries: Pakistan, Turkey, and Palestine.

His question: how often do Muslims pray versus how often do they claim to pray? In the March 2014 issue of Social Forces, Brennan said he found prayer was overreported in the Muslim world in a similar way to how church attendance was overreported in North America.

Brenner's 2011 study asked do people go to church as much as they say they do? To measure the gap between word and deed, Brenner examined two types of data from 1975-2008. The first were traditional surveys asking people how often they attended religious services. The second type of data was collected by having participants keep a time diary. (This was a sneakier way of finding out what people were really doing, say, on Sunday morning at 9:30.)

The differences between the two data sets were remarkable. Phillip found that between 35 and 45 percent of those surveyed said they went to church regularly, while the time diary method revealed that only about 25 percent of Americans actually attend weekly services. That means there's a gap of 10 to 18 percentage points between those Americans who say they go to church, and those who go to church. When he put this data in global perspective, Brenner found that the trend of overreporting is unique to the US and Canada.

This inflated sense of church attendance hasn't really changed much in the past few years. The Public Religion Research Institute recently confirmed that people fib about going to church. In a study published in May 2014 — humorously titled "I Know What You Did Last Sunday" — PRRI wrote that "every subgroup of Americans inflates their levels of religious participation." Here's a chart breaking down how different religious groups responded.

So what gives? Why are all these religious people lying? Is the trend in religious overreporting similar to the I-Work-Out phenomenon, when most of us check off that box at the doctor's office alleging we work out "4-7 days a week," when really the only energy we've exerted over the last month was during that one episode of Homeland when we lunged at the television.

NPR's Shankar Vedantam suggested it may be similar to our relationship to flossing: "Lots of people say they do it, not many people actually do."

According to Brenner, overreporting Muslims and Christians are not maliciously lying on surveys — they're mishearing the question.

Like the overreporting of church attendance in North America, the overreporting of prayer in the Muslim world is strongly associated with the individual's sense of what is central to his or her self-concept. The respondent interprets the conventional survey question about prayer pragmatically rather than semantically, allowing the question to become one about the respondent's identity, rather than actual behavior.

In other words, when a religious person is asked, "Do you do religious stuff?" the question she actually hears is, "Are you the kind of person who does religious stuff?"

If Brennan's and PRRI's research are any indication, lots of people in North America and the Middle East perceive themselves as the kind of people who do religious stuff — even when they're not actually doing anything.