Amidst a recent spate of travelling in Australia, I watched two films from that country, both released in the nineteen-seventies: Nicolas Roeg’s “Walkabout,” from 1971, and George Miller’s “Mad Max,” from 1979. I was struck by how much Roeg’s film felt of its time, and how little did Miller’s. It is true that eight years separate the two, bookending a decade—and one might argue that 1971 was, in essence, still the nineteen-sixties. But “Walkabout,” while it retains an impressionistic power, is filled with moments that jar for a different reason: they seem irrevocably dated.

Some of it is content. As Lee Siegel notes in an introduction to “Walkabout,” the novel on which the movie was based, “post-Woodstock, post-Manson, Roeg’s startling film is very much of its disillusioned moment, the early seventies, when the naïve enthusiasms of love-ins and flower children have given way to cynicism and despair.” The theme of savagery of nature versus savagery of civilization (the Aboriginal youth slaughters a kangaroo, the next shot is of chicken being trimmed in a butcher shop) that runs throughout is, as Siegel politely puts it, “now familiar.” But there are stylistic date stamps as well: the soft focus, the out-of-order edits, the reverse zooms, the song “Los Angeles,” by Warren Marley.

By contrast, “Mad Max” felt remarkably fresh, as if it could have been made in the nineteen-eighties—or last week. But why? What actually makes a work of art—a film, a novel, architecture, fashion—seem “dated”? The Web site of Merriam-Webster defines dated as “outmoded, old-fashioned.” And yet, this lacks explanatory power; every historical artifact (not to mention some that are new and “already dated”) could fall under that rubric. Why do some things seamlessly slip from their temporal context? When does something cross from historically appropriate to “dated”? And is there a time window for datedness, a kind of reverse statute of limitations, beyond which things are doomed by their historical patina?

“Mad Max” certainly has its historical signifiers, like Max Rockatansky’s 1973 Ford Falcon XB GT coupe, but one secret, I think, is that the movie is not moored to any time. It opens with the vague phrase “A few years from now,” and, rather than any trappings of the fetishized future, “Mad Max” looks backward. At the end of the day, with its lone frontier rider trying to preserve order, it is a Western, with muscle cars. The costumes, the soundtrack, the peculiar mutterings of the outlaws (“Joviality is a game of children”) are at once familiar and slightly out of joint.

What makes a work of art seem dated, I would suggest, is a sort of overdetermined reliance on the tropes, whether of subject or style, of the day—a kind of historical narcissism. A director like Alfred Hitchcock seemed to go out of his way to avoid this fate, as discussed by the actress Eva Marie Saint in an interview:

Hitch had a theory about the wardrobe. He didn’t want it dated, and so he wanted everybody to wear clothes that were almost classic clothes. One day, I remember, we were doing I believe the auction scene, and I was in my black dress with the red roses. Everybody that day—especially the women—were in dresses that were without belts. That was kind of the chic look at the time. And he sent everybody home and we did some other scene.

In Hitchcock films, characters don’t use phrases like “daddy-o” or listen to Bobby Darin records, however current such details might been at the time.

Being au courant can be its own sort of stultifying endgame. As The Onion’s A.V. Club noted, for example, the television show “Kate & Allie,” a critic’s darling in the nineteen-eighties, “hasn’t aged particularly well because it was a show that came up with a ‘daring’ premise for the time—two divorced women live together after their marriages end—then figured its work was done.” Comedy, which so often is playing against conventions of the day—and, in a Twitter age, typically that day—seems to have the shortest sell-by date. You can listen to the routines of someone like Lenny Bruce and respect the craft, but how often are you actually laughing along with the audience?

Datedness runs in all kinds of temporal directions. Science fiction, the genre that should seem the least dated, can often feel the most, because the future as depicted came to pass and looked nothing like that. In the same way that period films often commit the mistake of showing everyone driving shiny new period cars (as those are the only ones that have survived to the present), science-fiction films often assume that the future, to paraphrase William Gibson, will be “evenly distributed”—that everything, from computers to clothes, will represent a radical break from today. A film like “Blade Runner,” however, reminds us that periodicity can be messy. As Gibson has written, the best way to write about the future is to write about the present.

Sometimes, of course, things are genuinely ahead of their time. In “The Architecture of Happiness,” Alain de Botton reprints a 1927 advertisement for Mercedes-Benz that depicts a woman, wearing gloves and a cloche (that iconic headwear of the twenties), one foot astride the running board. The woman and the car are posed in front of Le Corbusier and Pierre Jeanneret’s Double House, built for the Weissenhof housing project in Stuttgart. The photo reads like a children’s game: Which of these things is not like the others? The car and the woman are Jazz Age relics; the house looks like it could be have been built in Malibu last week. The irony is that the advertisement wants to depict all three as the quintessence of “modern,” but only the house, so stylistically out in front, kept on being “modern.”

Then there are curious quirks, like meta-datedness. A film like the 1974 adaptation of “The Great Gatsby” is not dated in the sense of trying to depict the nineteen-twenties; rather, it’s dated in how that depiction is influenced by what the nineteen-seventies thought the nineteen-twenties should look like. (You can judge for yourself how Baz Luhrmann’s version is going to age.)

I’m not suggesting that every artist should strive for some universal timelessness. We need anthropological totems like the cloying saxophones of nineteen-eighties pop and the harvest-gold appliances of nineteen-seventies kitchens. And, of course, the artist cannot shrewdly trade in some kind of cultural futures market, keenly anticipating and deflecting all the history to come, which will someday render his or her cutting-edge vision hopelessly shopworn by all that has happened between it and its contemporary viewing.