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Men are hiding something. Are they acting a bit furtive in the car? Asking for some privacy with their iPhone? What sin are they indulging in? Arbitron finally has exposed their dirty secret.

They've been listening to Barry Manilow.

Call it soft rock, light rock, adult contemporary; call it what the Grammys call it: pop vocal (though that’s a broad category). It's Cher, John Denver, Abba, Whitney Houston, James Blunt, and—the patron saint of all soft rock—Céline Dion. And Americans, particularly men, listen to more of it than you might expect.

According to the latest release of Arbitron's radio ratings, men reportedly listen to 6% more soft rock than they have admitted to in past surveys. Here's the rundown: Arbitron, radio's main ratings-gatherer since its inception in the 1960s, has until 2007 collected its information by way of written radio diaries. Arbitron would distribute about 800,000 blank booklets to radio listeners nationwide, asking them to record their radio listening habits for one week. The collected data was radio’s answer to the Nielsen ratings.

With one difference: in 1987 Nielsen stopped using self-reported data and began using remotely metered measurements, taken by set-top boxes placed in about 9,000 homes. It wasn't until 2007 that Arbitron followed suit, inaugurating the "Portable People Meter" or PPM, a device that radio listeners carry around all day, recording which stations they tune in to. As it turns out, the differences between self-reported and remotely-measured radio use are, well, substantial.

Men, it appears, tended to underreport the amount of soft rock they listen to. The PPM shows that 6% more men listened to soft rock in 2008 than was reported in this 2007 report. That's right: more Céline Dion, Barry Manilow, the Doobie Brothers, Chicago, Barbra Streisand, Elton John, and The 5th Dimension (“Aquarius/Let the Sunshine In”)—all Grammy winners for Best Pop Vocal, by the way.

Some other stand-out revelations from the PPM? Americans listen to less classical and less jazz—two already-ailing radio genres—than previously thought. The majority of Americans still listen to radio: the odds a man will listen to network radio in a week are 1 in 1.37 (73%), and the odds a woman will do the same are 1 in 1.39 (72%). But jazz and classical are two of the least-listened-to radio genres.

Genres with the most market shares are adult contemporary, urban adult contemporary, country, and news/talk radio. For example, the odds an adult listens to NPR (from the last category) regularly are 1 in 5.88, the same odds an adult 18 - 29 who owns a cell phone uses it for instant messaging.

As for why so many men appreciate soft rock, singer-songwriter Jonathan Coulton proposes one answer: it emboldens the doormat in each of us to be a Don Juan. As he puts it, "When I soft rock you / you will know it's true / that you've never been soft rocked until you've been soft rocked by me."