In her brilliant final book, “Regarding the Pain of Others,” Susan Sontag noted that “the appetite for pictures showing bodies in pain is as keen, almost, as the desire for ones that show bodies naked.”

Sontag was writing primarily about still photographs and paintings, but her essay touched on perhaps the most enduring and disquieting impulse of cinema, one that’s on particularly extravagant display this season.

Both “The Hateful Eight” (now showing) and “The Revenant” (opening soon) make promiscuous use of bodies in pain. Directed by Quentin Tarantino and Alejandro González Iñárritu, respectively, both films are set against the pitiless, snowy backdrop of the 19th-century American West. And both traffic in lingering wide-screen images of savage brutality and mortification, as their protagonists claw, fight, shoot and stab their way to preserving their own lives.

In “The Hateful Eight,” an ensemble of actors gathers in an isolated cabin that becomes an improbably cozy backdrop for the usual Tarantino descent into cartoonish gore and mayhem. In “The Revenant,” a trapper named Hugh Glass, played by Leonardo DiCaprio, is mauled by a bear, his back, chest and throat horribly mutilated; left for dead by his fellow travelers, he literally crawls his way back to life, driven by a primal desire to avenge his presumed death.

It’s possible to appreciate both films, even admire them, for their sheer ambition and near-flawless execution. But the virtuosity on display also produces its share of deep misgivings. Whether by way of Tarantino’s ironic distance or Iñárritu’s artily masochistic extremes, it’s genuine empathy and self-reflection that get short-circuited, swamped by surface values of aesthetics, technical achievement and shocking, vicarious jolts.

SUFFERING FOR THEIR ART

Tarantino and Iñárritu have long made their characters and audiences suffer for their art, each in his own way depicting human misery with an unsettling combination of detail and aestheticized detachment. The vicious assaults and bloodletting of “The Hateful Eight” have Tarantino’s usual quote marks around them, with his protagonists barely blinking an eye when their bodies are ravaged and riven, tortured and abused. By contrast, every excruciating moment of Glass’s journey is drawn out and solemnly lingered over in “The Revenant,” in which Iñárritu continually – and finally ludicrously – raises the ante with increasingly improbable stunts, each more shudder-inducing and poetically filmed than the last.

We’re meant to be mightily impressed by “The Revenant,” and it is, admittedly, notable for its stunning visuals and as a showcase for DiCaprio’s uncompromising physical performance. Less convincing is the reflexive – and false – equivalence of suffering and moral seriousness. That link is such a frequent movie trope that Iñárritu felt compelled to give Glass a fictional Native American wife and son, the better to elevate his motivation into something more spiritually acceptable than grubby, earthbound vengeance.

Even softened by Iñárritu’s philosophical pretensions, “The Revenant” is essentially a fetish film, guided by the same grindhouse aspirations of “The Hateful Eight.” Both movies are set up as endurance tests, designed to elicit awe at the physical extremes it took to film them.

They also present an implicit dare to audiences far more inured to seeing bodies in pain, to use Sontag’s construction, than bodies that are naked. In a recent survey conducted by the ratings board of the Motion Picture Association of America, parents evinced far more concern about sexual content and nudity in movies as opposed to violence, with 64 percent of respondents listing graphic violence as their chief concern, compared to 80 percent listing sex.

Violence has been an essential part of the cinematic lexicon from the medium’s inception. But what began as a symbolic way to confront our darkest impulses and grapple with our inevitable mortality has morphed into a gruesome game of one-upsmanship and endurance.

INEXORABLE ESCALATION

Like the proverbial frogs in pots of simmering water, filmgoers have tolerated escalating stakes in cinematic ghastliness at least since 1960, when Alfred Hitchcock created the first slasher film with “Psycho.” Since then, the graphic language of human misery has followed parallel, sometimes intersecting tracks, one leading to the extremities of “Saw”-like torture porn, the other to such “sophisticated” adult dramas as “The Silence of the Lambs” and “Seven,” both of which introduced new layers of depravity to the otherwise staid genre of the psychological thriller. This is the voyeuristic, self-serious cultural space that “The Hateful Eight” and “The Revenant” occupy, cannily ginning up and manipulating emotions, but rarely going much deeper.

Suffering has also been a longtime mainstay of film grammar, and not always necessarily predicated on violence. In two recent films – Michael Haneke’s 2012 drama “Amour,” as well as this year’s intimate mother-son drama “James White” – the sight of loved ones caring for one another through the messiest moments of life and death becomes a way to bear witness to compassion, self-sacrifice and resilience.

Those films represented even the most unsavory aspects of their subjects with sometimes startling directness. But, when conveying unspeakable anguish, there’s just as much power in the oblique. In “Son of Saul,” Laszlo Nemes follows an Auschwitz prisoner as he moves through the camp, its now-familiar atrocities playing out on the blurry edges of the frame in a radical reordering of conventional “Holocaust film” iconography that feels shatteringly immediate and new.

EQUALLY AWFUL

Two of this year’s finest films, “Room” and “Spotlight,” deal with similarly wrenching subject matter, without being dishonestly coy or grimly exploitative: One is a portrait of a woman who’s been kidnapped and repeatedly raped, often in the presence of her young son, who was conceived while she was in captivity; the other chronicles a journalistic investigation of child sexual abuse within the Catholic church.

In “Room,” a sexual assault is depicted quietly, just outside the boy’s view, his mother’s despair, terror and helplessness made palpable in the dim shadows outside a closet door. In “Spotlight,” rather than scenes of molestation, victims tell their stories with hushed forthrightness. If anything, the film’s most emotionally shattering scenes are the most indirect, such as when an elderly woman asks for a glass of water after reading about the church’s crimes, or when an attorney, played by Stanley Tucci, greets a family of victims with a bonhomie carefully cultivated to mask the anger and grief that threaten to overwhelm him and the audience.

The difference between these films and the exercises in style of Tarantino and Iñárritu comes down to what’s being demanded of the audience: Whereas “The Hateful Eight” and “The Revenant” encourage us to sit back and be dazzled, “Son of Saul,” “Room” and “Spotlight” call on each viewer’s memory, conscience and moral imagination to complete the picture and create its deepest meaning.

Every time the lights go down in a movie theater, the filmmaker extends an invitation to the audience: to be passive spectators or active collaborators, to see suffering as a spectacle or a struggle to be honored, to have our hearts hardened or opened. Regarding the pain of others has always been part of going to the movies. Most likely, it always will be.