At the Billboard Music Awards on Sunday night, Miley Cyrus’s younger sister (the emergent pop star Noah Cyrus, who sings in a comparably billowy voice) and her father (the country singer Billy Ray Cyrus, whose songs have a strange and clangorous twang) stood together to address the crowd. It immediately felt like collusion: the product of a conference-room meeting in which someone said, “O.K., let’s get this story straight.”

“Miley is always speaking her truth and being herself,” Billy Ray said, by way of explanation.

“For the first time in years with pants on, my big sis, Miley Cyrus,” Noah shrieked, by way of clarification.

When the camera cut to Miley, she was not wearing pants, per se, but was dressed somewhat more demurely than in recent years, in white shorts, a white off-shoulder cropped top, boots, and a floppy hat. None of her tattoos were visible, which felt notable because Cyrus has many, including several on her shoulders and forearms. She wore her hair long, blond, and artfully tousled. Footage of crashing waves flashed behind her. She stood close to the microphone, her hands gripping the stand. This particular pose is more familiar to a solemn ballad singer, like Adele, than to a young pop star like Cyrus, who was once briefly, stupidly infamous for her incessant twerking, a dance move in which a woman bends over and aggressively gyrates her buttocks.

The aesthetics of the Billboard performance plainly mirrored the video for Cyrus’s new single, “Malibu,” which she released earlier this month. It was filmed along the central California coast, and in it Cyrus wears all white, pets a dog, runs with balloons, and flashes her gold engagement ring. At one point, she does a funny little jig with her hands on her hips, kicking her feet out willy-nilly. It is the exact sort of dance a middle-aged person might do after she has had one too many cups of white wine in the park.

Onstage, Cyrus did not do this dance, but she did begin crying toward the end of the performance. She also clutched her heart, just as she sang the word “heart.” Musically, “Malibu” is a mix of Laurel Canyon and Nashville, equal parts bohemian and smarmy; it is as if Dolly Parton were finally called upon to sing a late-era Stevie Nicks track. Cyrus sounds lifeless on it. This is too bad, because Cyrus has a rich, husky voice, and, when she inhabits it with more gusto, like on her previous singles “The Climb” and “Wrecking Ball,” it conveys both fragility and tremendous strength. (I still find it hard to get through the bit in “Wrecking Ball” when Cyrus, voice cracking, sings, “Don’t you ever say / I just walked away / I will always want you,” before slamming into that colossus of a chorus.)

Historically, Cyrus has been a creative risk-taker—a practice that periodically backfires and gets her in trouble with her public but has nonetheless made her a figure to root for. It always felt, to me, like Cyrus was methodically working her way toward something interesting; we just needed to wait, to forgive her trespasses, to let her figure out what moved her. But “Malibu” is such a vigorous left turn that it casts her prior experimentalism (which reached a funny kind of apex—or nadir—with “Miley Cyrus & Her Dead Petz,” the 2015 album she made with Ariel Pink, Big Sean, and members of the Flaming Lips, and then gave away for free) in an ugly light. Her famously cavalier borrowing of black culture, on songs like “We Can’t Stop,” from her 2013 album, “Bangerz,” or Mike WiLL’s “23,” on which she raps (“I’m naughty by nature, I’m like hip-hop hooray”), is especially troubling to consider now. As Zeba Blay pointed out on the Huffington Post, Cyrus’s casual trying-on and discarding of black culture is a function of extraordinary privilege. That she has essentially scrubbed her music and image of any hints of the hip-hop and R. & B. she once lauded and imitated makes her previous embrace of those genres feel disingenuous, if not sinister.

“Malibu” is presumably about Cyrus’s relationship with her fiancé, the actor Liam Hemsworth, whom she met in 2009, on the set of “The Last Song,” an adaptation of a Nicholas Sparks novel. They broke up, got engaged, broke up again, and got engaged again. The song is a kind of stocktaking, as Cyrus looks back in amazement at the situation she now finds herself in: reunited with a lost love, and wearing a turtleneck on the beach. “I never would’ve believed you if, three years ago, you told me I’d be here writing this song,” she sings.

The whole good-girl routine would feel like a sendup—a comment on the pliability of persona, or on pop costuming, both literal and figurative, or on our racially polarized political climate—if that kind of commentary were Cyrus’s thing. But it’s not—when I spoke to her in 2014 (back then, she and Hemsworth were done, she was dating a woman, and had taken to sticking her tongue out all the time), I was struck by how earnest she seemed about everything. She pulls from a seemingly bottomless font of sincerity; on the telephone, she would periodically get so riled up I’d have to ask her to stop pressing the phone to her face because all I could hear was beeping from the buttons.

Most everybody readily acknowledges the artifice inherent to pop music—as consumers, we know and understand, to some degree, that the whole business is and always has been an aggressively managed charade. Part of the deal is that we still feign chagrin or incredulity (or both) when a pop star announces another reinvention. These shifts aren’t so interesting for what they broadcast about the state of an individual performer’s philosophical posture—in fact, I’d argue that, in that regard, they’re largely meaningless; far more compelling is what they indicate about an artist’s commercial potential, which is inextricably tied to the public’s hunger for change, and for new and flashier iterations of the same thing, and, in this case, for strange archetypes made real.

Cyrus herself has been through this before: she was the star of “Hannah Montana,” a wholesome television series on the Disney Channel, long before she was miming a cornucopia of sex acts onstage with Robin Thicke. It’s famously difficult for young women to navigate these transitions and find purchase. Pop singers seeking colossal stardom tend to operate in only one of two modes: guileless, fresh-faced ingénue; or a sex-starved, lingerie-clad vixen. (“Regular” has yet to become an especially profitable option.)

Cyrus’s arc—she was a fairly innocent kid who enjoyed a wild period in her early twenties, and, now that she’s about to become someone’s wife, she’s settling down, finding a new way to be (or act) virtuous—is culturally ingrained. Everyone seems to agree that this is an acceptable path forward. And that’s what’s so troubling about it. It’s not so much that Cyrus has changed (or that she has, at least, changed tack strategically; both are so ordinary as to be banal), it’s that this is what everybody thinks a grownup woman looks like: pretty, tamed, straight, still, white. (The virginal outfits are nearly funny in their broad strokes—did no one in her circle think to say, “A little on the nose”?)

Performing adulthood becomes dangerous when the performance is so limiting. The idea that a woman grows up only by settling down was reiterated in the finale of HBO’s “Girls,” when Hannah Horvath, the show’s protagonist, became pregnant and took a job teaching at a college upstate, a move that facilitated a kind of spiritual epiphany. For young women, this is a narrow path forward: become less selfish and wayward only by embracing antiquated notions of femininity and propriety. Is there not some functional middle ground to occupy? Cyrus’s about-face is so sharp, it obliterates any chance for a more subtle and multitudinous understanding of personal progress. It’s hard not to pine for that wagging tongue.