Daughter Francesca and I have been humming holiday music nonstop, which got us wondering why it's so appealing. I thought I'd let her answer that hard question, since I take only the easy ones, so she's writing the column today:

Growing up, we always played the same three Christmas CDs: Frank Sinatra, Tony Bennett and Charlie Brown. And, of course, I bought that Mariah Carey one so that I could listen to "All I Want for Christmas Is You" on repeat every year through most of the '90s. Now that I'm freshly on my own (and more interested in gifts under 20 bucks), everywhere I turn I notice another recording artist promoting a new album of yuletide tunes.

The funny thing about holiday CDs is, we already know the songs, and the singer is almost an afterthought. Normally, I buy a disc where my favorite artist does songs I've never heard before. On holiday CDs, an artist I may not even like does songs I've heard a hundred times - and I love it!

So it's no wonder performers love cranking out these holiday CDs; they get a free pass. Even obscure, outdated or talent-challenged artists can put out a seasonal album, and we, the discerning public, will go easy on them. It's Christmas, after all.

But some stars really test our generosity. For instance, someone named Lady Gaga teamed up with someone named Space Cowboy to record "Christmas Tree." I don't know who either of those people is, but somehow I thought their title would be a little more creative.

Or take George Michael. In September, he was arrested for crack-cocaine possession in a public bathroom - not to be confused with his 1998 arrest for lewd conduct in a public bathroom - but that didn't stop him from recording a new holiday track, "December Song (I Dreamed of Xmas)." I'm all for second (or third, or fourth) chances, but I think it's safe to assume that George is on Santa's naughty list. He might have asked for community service, but he's getting a lump of coal.

The all-time lows of Christmas music have to be those Jingle Dogs and Cats albums, where dogs bark and cats meow to the tune of holiday classics. Have you longed to hear "Angels We Have Heard on High" in a head-splitting caterwaul? Me neither.

It's a shame there aren't as many Hanukkah albums, but on the upside, at least they don't have cats singing, "Dreidel, dreidel, dreidel."

To me, Josh Groban is the newborn king of the modern holiday CD. His Noël was last year's biggest-selling album of any genre. That floppy-haired cutie with the powerhouse pipes gets me - and at least 3.7 million other people - every time.

So why do we buy these albums? We often say holiday music puts us in the holiday spirit, but what do we mean?

I remember reading somewhere that music directly accesses the emotional part of the brain, and I believe it. Music is a language that our hearts and souls can speak. The holidays are a time when we want to get into an emotional and spiritual frame of mind, and these songs unlock something inside us.

That Sinatra album is the same music that played when I was little, unwrapping presents in our apartment. The Charlie Brown CD my mom will put on this year is the same that was playing the year that our old dog Lucy, then just a puppy, knocked over the Christmas tree. The songs Josh Groban sings are the same ones I sang when my high school chamber choir went caroling in the halls.

I love that music, because I love those memories.

These familiar songs remind us of family, childhood, a time when it was safe to be vulnerable and safe to believe. After a year of steeling ourselves against life's hardships, stresses and fears, now is a time when we can let down our guard. Music softens us, so that we can come into the warmth of family and un-bundle, so to speak. Because at some point, when everyone is gathered around the table, talking over each other and laughing, and the voices get louder, some voices you hear every day and some not often enough - well then, anything else is just background music.

Lisa Scottoline is a best-selling author of 15 novels. Her daughter, Francesca Serritella, is a budding writer and an honors graduate of Harvard College, majoring in English.