Even noteworthy filmmakers may not see what they’re doing. They can reveal crucial aspects of their work inadvertently, bringing to light the cinematic unconscious, hinting at what a movie could and should have been. That’s what Alfonso Cuarón, the writer and director of “Roma,” did in an interview for a recent magazine article. Set in Mexico City in 1970-71, “Roma” depicts a family much like the one in which he was raised and is centered on a domestic worker, both maid and nanny, named Cleo Gutiérrez (Yalitza Aparicio); the character, Cuarón has said, is based on a woman named Libo Rodríguez, who played a similar role in his childhood (and to whom the movie is dedicated).

In the article, the journalist Kristopher Tapley conveys the substance of Cuarón’s inspiration for “Roma”: “Rodríguez would talk to Cuarón about her hardships as a girl, about feeling cold or hungry. But as a little boy, he would look at those stories almost like adventures. She would tell him about her father, who used to play an ancient Mesoamerican ballgame that’s almost lost to the ages now, or about witch doctors who would try to cure people in her village. To him it was all very exciting.”

Watching “Roma,” one awaits such illuminating details about Cleo’s life outside of her employer’s family, and such a generously forthcoming and personal relationship between Cleo and the children in her care. There’s nothing of this sort in the movie; Cleo hardly speaks more than a sentence or two at a time and says nothing at all about life in her village, her childhood, her family. She’s a loving and caring young woman, and the warmth of her feelings for the family she works for—and theirs for her—is apparent throughout. But Cleo remains a cipher; her interests and experiences—her inner life—remain inaccessible to Cuarón. He not only fails to imagine who the character of Cleo is but fails to include the specifics of who Libo was for him when he was a child.

In the process, he turns the character of Cleo into a stereotype that’s all too common in movies made by upper-middle-class and intellectual filmmakers about working people: a strong, silent, long-enduring, and all-tolerating type, deprived of discourse, a silent angel whose inability or unwillingness to express herself is held up as a mark of her stoic virtue. (It’s endemic to the cinema and even leaves its scars on better movies than “Roma,” including some others from this year, such as “Leave No Trace” and “The Rider.”) The silent nobility of the working poor takes its place in a demagogic circle of virtue sharing that links filmmakers (who, if they offer working people a chance to speak, do so only in order to look askance at them, as happens in “Roma” with one talkative but villainous poor man) with their art-house audiences, who are similarly pleased to share in the exaltation of heroes who do manual labor without having to look closely or deeply at elements of their heroes’ lives that don’t elicit either praise or pity.

That effacement of Cleo’s character, her reduction to a bland and blank trope that burnishes the director’s conscience while smothering her consciousness and his own, is the essential and crucial failure of “Roma.” It sets the tone for the movie’s aesthetic and hollows it out, reducing Cuarón’s worthwhile intentions and evident passions to vain gestures.

“Roma” is the story of a family in Mexico City’s Colonia Roma neighborhood (where Cuarón grew up): father, Antonio (Fernando Grediaga), a doctor; mother, Sofía (Marina de Tavira), a biochemist who is running the household and not working; grandmother, Teresa (Verónica García), who is Sofía's mother; and four children (a girl and three boys), ranging, seemingly, from about six to about twelve. And then there’s the household staff, Cleo and Adela (Nancy García García); there’s also a man who drives the family car, but he is utterly uncharacterized.

The youngest child, Pepe (Marco Graf), an imaginative boy who talks about being a pilot, seems to be the Cuarón stand-in, though the movie isn’t dramatized from his point of view. (I’ll avoid disclosing some major plot developments.) The family is solidly upper middle class; they live in a house separated from the city street by a gate and divided from neighboring houses by an alley, in which they park their cars (and in which the family dog, Borras, runs loose and defecates). Antonio, who claims to be heading to Quebec for a temporary research project, actually remains in Mexico City, simply having left his wife and family in order to live with another woman.

Meanwhile, Cleo, quiet and patient, has her own romantic dreams: she’s dating Fermín (Jorge Antonio Guerrero), a cousin of Adela’s boyfriend, Ramón, and becomes pregnant. The family sympathizes with her; Cleo continues to work for them and receives good medical care, thanks to the family’s connection to a major urban hospital. But trouble ensues when Cleo goes on a shopping trip with Teresa, during a day of student protests; they know that such protests have been violently repressed, but this time the violence is worse than before, and Cleo and Teresa observe it up close. (Cuarón is dramatizing an actual historic crisis, the Corpus Christi Massacre, of 1971, in which soldiers and paramilitaries gunned down student protesters in the streets of Mexico City and pursued them into their hiding places and refuges, including hospitals.)

Cuarón expands the story with copious, carefully observed—rather, carefully constructed and planted—details that, for the most part, rather than developing a wide-ranging and deep-reaching view of the life of the family and its times, lines them up and points them all in the same direction. But, because his view of Cleo is willfully, cavalierly vague, his view of the public and historical events in which she becomes entangled, and which he dramatizes, is similarly flattened and obscured.

For instance, when Cleo learns that she’s pregnant, she’s seen sitting pensively at the window of the small garret room that she shares with Adela. Does she give any thought to abortion? What was the law on the subject in Mexico at the time? Was the practice common, regardless of legal strictures? Or consider the political context that Cuarón places into the story. There’s an ongoing issue regarding land use and ownership; the family’s wealthy friends living on a large estate are in a dispute with poorer local residents over land, and the conflict turns deadly. What are the issues in question? It’s all the odder that the movie remains vague when Adela mentions that Cleo’s mother’s land, in her native village, is being confiscated. What were the specifics of the political conflicts in Mexico then?

Cuarón sets up the story of the Corpus Christi Massacre with a close view of the training of the paramilitaries (with a hint—but only a hint—of the C.I.A.’s involvement). Yet here, too, he empties the conflict of its ideas. What are the students protesting? What are they advocating? Why do they seem to threaten the regime? In a scene of a political campaign (a rather absurd one, featuring a human cannonball launched into a net) in a distant village, where unpaved streets are fetid with standing water and basic infrastructure is the Presidential candidate’s main promise, Cuarón suggests that Mexico was, at the time, at least a semblance of a democracy. But the film doesn’t make clear whether it was actually democratic, whether censorship was stringent, whether ordinary people, such as the family at the center of the film, lived in fear of repression.