Which is a shame, because Mr. Bieber is developing into a gifted vocalist, far less reliant on technology than he was two years ago. His voice is limber and wounded, more credible when begging or retreating, as on “Fall” and “Right Here,” than when aiming to steam up the room, as on “Out of Town Girl.” And his falsetto consistently connects. He’s confident enough to weave a boast about it into the lyric of “Boyfriend”: “I dunno about me but I know about you/So say hello to falsetto in three, two,” which is then followed by an angelic, tender serenade. Many of the best songs on “Believe” are young-love ballads, the sort that would have been credible for Mr. Bieber even a couple of years ago, though he might not then have had the voice to deliver them properly.

And so Mr. Bieber is not yet fully grown, and in his real life, he’s been doing his best to maintain at least a veneer of young-person normalcy. His hair, which formerly suffocated his forehead — giving him a signature look he couldn’t shake — is now mostly swept up and back, in the manner of most young bros. When the paparazzi catch him out with his girlfriend, the singer-actress and former Disney star Selena Gomez, they’re doing frustratingly normal things: eating Subway in a park, or picking up Chick-fil-A at the drive-through (though at least he’s driving his new chrome Fisker hybrid sports car, an 18th birthday gift from his manager).

The last male teen-pop star who matured so publicly was Justin Timberlake. But he had more armor: he was emerging from a boy band, ’N Sync, and he didn’t release his first solo album until he was 21. That album, “Justified,” not only established Mr. Timberlake as an adult, but also was a landmark pop album, at the outset of the moment when hip-hop producers began to make records for pop stars. Mr. Timberlake was setting pop’s agenda.

Mr. Bieber doesn’t have Mr. Timberlake’s backbone, or his experience, or his raw talent for that matter. So, perhaps wisely, he’s looking elsewhere for models of how he can publicly mature. Actually he’s aiming higher, conjuring perhaps the biggest and most conflicted teen star of all time, Michael Jackson. Jackson is sampled outright on “Die in Your Arms,” which borrows its loose jangle from “We’ve Got a Good Thing Going,” from the album “Ben,” released when Mr. Jackson was just 13. Mr. Bieber hones his vocals into a constrained yelp here, a sound that’s decidedly Jackson-esque, and not nearly as smooth as Mr. Bieber’s typical vocal approach.

But the real wink comes on “Maria,” the final bonus track on the deluxe version of the album. Last year a woman named Mariah Yeater accused Mr. Bieber of being the father of her child. It was the first true adult scandal for Mr. Bieber, who’s never had to project the outright sexlessness of his Disney-raised teen pop peers, but who was nevertheless still a teenager when the charges landed, and no tabloid regular.