A new commercial for Taco Bell opens with an actor with shaggy, Don Johnson hair, in a white oversized blazer with shoulder pads, pulling a McDonald’s sandwich from a paper bag. To the tune of “Old MacDonald,” he sings, “I’ve been eating Egg McMuffins since 1984.” The scene then cuts to a schoolboy, his younger self, wearing the same outfit and eating the same Egg McMuffin, this time from a Styrofoam clamshell box. Later in the commercial, the character breaks free of his nineteen-eighties trance: he gets his hair cut, trades in his white blazer for a hoodie, finally throws out his Loverboy poster—and heads out for a Waffle Taco.

Taco Bell wants to sell more breakfast food, so it’s trying to get new customers by poking fun at McDonald’s for failing to update its menu. What’s incongruous about the commercial is that the Egg McMuffin was already a big seller in the seventies, yet Taco Bell’s character isn’t singing about that era. He’s not wearing bell-bottoms; in his outdated living room, you won’t find a lava lamp or a disco ball.

For advertisers, the eighties are suddenly the decade to strip-mine for memories. During the Super Bowl, RadioShack débuted a self-mocking commercial with pop-culture icons such as Mary Lou Retton, Hulk Hogan, and Teen Wolf clearing the store of its old boom boxes and fax machines. Its punch line is “The eighties called—they want their store back.” (The background music, incidentally, is Loverboy.)

On April 26th, Microsoft plans to dig up a landfill in Alamogordo, New Mexico, where it believes millions of unsold “E.T. The Extra-Terrestrial” Atari cartridges may have been buried in 1983. Microsoft’s Xbox Entertainment Studios is funding a documentary about the excavation. At Delta Air Lines, a new, eighties-themed flight-safety video shows a passenger putting an oxygen mask on the TV character ALF; girls with poufy side ponytails switch seats to avoid blocking the aisle.

Toying with the past is a perennial marketing tactic. “Nostalgia is a fun area to play with because it’s relatable and brings back great memories, while also reminding us how quickly the world evolves,” Chris Brandt, Taco Bell’s chief marketing officer, told me.

At RadioShack, the idea for the Super Bowl commercial came from focus-group participants who accused it of being stuck in the eighties. The company decided to own up to its image, while explaining that it had, indeed, remodelled its stores since the Reagan Administration. “There were so many memories associated with the decade that we realized we were onto something,” Jennifer Warren, the chief marketing officer for RadioShack, told me. “I was a big Cyndi Lauper fan, and I remember teasing my hair.”

The eighties might also be the last era associated with an exuberant visual vernacular. The nineties are too dour for marketers—try selling a Waffle Taco with Kurt Cobain and dark flannels. Of course, the eighties often weren’t much fun, either, with the Cold War, the AIDS epidemic, the Challenger explosion, Chernobyl, and Tiananmen Square. (The actor Kevin Bacon, in a recent fake public-service announcement for Millennials called “’80s Awareness,” spoofed the mood of the decade by snarling, “You couldn’t even skateboard to a Blockbuster without getting nuked.”) But when you excise the actual news from our collective memory and are left with neon leg warmers and keyboard guitars, the eighties at least look fun.

Of course, we have to get some distance from any era in order to form a consensus about what it meant. Since the nineties, though, it’s become more difficult to define the aesthetic of a particular decade. This might have something to do with the fragmentation and the proliferation of media, and with the fact that so much of our cultural experience is now virtual rather than physical. It also relates to the democratization of fashion; a few big brands can no longer dictate a look. Valerie Steele, the director of the Museum at the Fashion Institute of Technology, told the Times that, if people in the future want to throw an aughts-themed event, “it does seem like it would be harder to dress for the party.” The character in the Taco Bell commercial, once he cuts his hair and changes his clothes, looks like he could slip into any moment in the past thirty years.

It’s too soon to tell how the ads will translate into sales. Two years after it created the wildly popular Doritos Locos Taco, Taco Bell is looking for its next hit with the Waffle Taco. RadioShack’s makeover is proceeding: a month after its Super Bowl commercial aired, the company announced plans to close more than a thousand stores. Warren said that RadioShack franchise owners report that new customers are still talking about the ad.

By choosing the eighties, marketers are taking advantage of what we know about when people experience nostalgia. As people enter their fifties and begin to take stock of their lives, they become more susceptible to nostalgia, according to Erica Hepper, a psychologist at the University of Surrey and a leading researcher on the subject. Because we tend to form lifelong preferences in our early twenties, adults in their fifties are now nostalgic for the nineteen-eighties—the time when their lives seemed full of promise and their tape decks were blaring heavy-metal bands. That thirty-year retrospective glance might explain the popularity of “Back to the Future,” a 1985 movie set in the nineteen-fifties, or why “That ’70s Show” was a television hit in the early aughts. (Adam Gopnik has written about a similar cycle, which he calls the Golden Forty-Year Rule.)

But Taco Bell’s target customers are Millennials, most of whom weren’t even born in the eighties. Microsoft and RadioShack want to reach younger shoppers, too. So does the nostalgic approach make sense in these cases? According to Hepper’s research, the other time nostalgia tends to peak is when people are in their late teens and early twenties. They’re facing a series of anxious life transitions, such as starting a career and moving out of their parents’ homes. Millennials, in particular, are facing a tough job market and crushing student loans.

People can feel a vicarious nostalgia for an era they didn’t actually live through: witness the appeal of Renaissance fairs, or of steampunk subculture, with its quasi-Victorian costumes. Millennials know more about the eighties than might be expected, partly because of all the TV reruns they watched as kids. Warren, the RadioShack marketing executive, recalls that when she asked people in their early twenties if they recognized ALF or John Ratzenberger, who played Cliff on “Cheers,” they scoffed, “Of course,” as if she were insulting their intelligence. In this context, Taco Bell’s choice of the eighties rather than the seventies for its Waffle Taco commercial starts to make a lot of sense; according to a spokesperson, the company set its ad in the eighties specifically to appeal to Millennials.

Nostalgia can be a tricky emotion to exploit. It can associate a product with happy memories—making us feel both emotionally and physically warmer—but it also carries a sense of loss. In a memorable episode of “Mad Men,” Don Draper explains a pitch for the Kodak carrousel slide projector by saying, “It lets us travel the way a child travels, around and around and back home again, to a place where we know we are loved.” One man leaves the room sobbing. In the new eighties ads, the satire and the upbeat music prevent things from becoming treacly. “When you look back at pictures of the eighties, it was a ridiculous decade,” RadioShack’s Warren said. Plus, it’s hard to be sad when you’re rocking out to Loverboy.

Photograph by Paul Natkin/WireImage/Getty.