In the Britney zone

It happens to all Barbies at some point. The little girls who once idolized them grow up and lose interest, leaving them on the shelf as a reminder of quaint, preteen days gone by.

Seeking to avoid that fate with her fourth album, "In the Zone," Britney Spears is now in search of a new, edgier identity. But while trying to recapture fans who have moved on to newer, edgier pop stars -- Pink, Avril Lavigne, even ex Justin Timberlake -- Spears ends up sounding more juvenile than ever.

The former Queen of Teen Pop, who on her last album reminded us that she was "not yet a girl, not yet a woman," is going out of her way to show us she's all grown up. We've seen the 21-year-old Spears undressed so often, it's become shocking to see a clothed Britney.

Add her lip-lock with Madonna, smoking and tales of wild parties, and the former Mousekeeter seems to have turned into a Girl Gone Buck Wild.

"In the Zone," released Tuesday by Jive Records, is a celebration of her newfound freedom and debauchery, with Spears sounding like a college freshman who's just discovered the party house on sorority row.

"Passed out on the couch and yawnin', just walked in and it's three in the mornin"' she coos on "Early Mornin'," while on "(I Got That) Boom Boom," the Ying Yang Twins shout, "We're going to the club to get drunk with Britney!" Too bad it's not as fun listening to this album as making it.

The majority of the disc is pretty insipid. That's not any different from any other Britney album, but with all the heavy hitters involved -- R. Kelly, Moby and Madonna -- this time the disappointment is more surprising.

Part of the reason the album fails is because for all her proclamations about being an adult, Spears still sounds like she hasn't grown up very much -- emotionally, vocally and most importantly, artistically.

There are sensual, driving dance beats that pick up where 2001's "I'm a Slave 4 U," left off. But it's hard to get into them with Spears sounding like a little girl trying to act sexy.

While Spears may not be the most talented singer, she still has some semblance of a voice, and comes off stronger when she tries to use it, like on the entrancing "Toxic" with its catchy string arrangement.

Instead, she resorts to moaning and heavy breathing on the bump-and-grind trance grooves "Breathe on Me" and "Touch of My Hand," a tender love story between a girl and her hand. The end result sounds artificial and forced.

But it's not always Spears' fault when the songs go bad. The R. Kelly-penned song "Outrageous" is outrageously silly. "Outrageous! My sex drive! Outrageous! My shopping spree! Outrageous! We're on a world tour!" Spears warbles, sounding like a "Saturday Night Live" parody, or maybe the theme song for Paris Hilton.

And Spears and Madonna generated more heat smooching on the MTV Awards than they do on the vapid "Me Against the Music," proving that simply throwing two superstars together isn't enough to make a hit.

There's also a sappy ballad, "Everytime," which is only worthwhile listening for tabloid fans playing pop psychologist, trying to discern if it's the epilogue of her much-dissected breakup with Timberlake.

Making the transition from teen star to adult performer is always a tricky adjustment, and plenty of singers have stumbled along the way -- we need only look back to Christina Aguilera's embarrassing peep video "Dirrty" to be reminded of that.