Vince lent Kristen a spare quarter outside a Metrodome payphone. The favor set in motion their fledgling romance.

The Palyans, two University of Minnesota alumni who met in the late 1980s, have now been married 25 years.

Fast-forward nearly two decades.

Engulfed by study notes during fall semester finals, a ting from Adam Baker’s phone bore the fruit of a potential relationship.

A new message from Tinder appeared on the University psychology sophomore’s screen — “Congratulations! You have a new match!”

It was from Grace LaPrairie, a business and marketing education sophomore whose bio read: “I flirt exclusively thru gifs.”

Moments later, LaPrairie sent a moving image of a waving baby seal — her way of saying “hello.” It wasn’t long until the two went out for pizza. Six months later — despite fears of judgment from friends and family — the couple are still together.

LaPrairie and Baker’s story has become increasingly common among young people, who have embraced the digital dating phenomenon in recent years. The number of 18- to 24-year-olds using online dating sites or mobile apps nearly tripled from 2013 to 2015, from 10 percent to 27 percent, according to a study from the Pew Research Center.

And about half of single adults in the U.S. have tried online dating, 2010 U.S. census data shows.

In the late 1600s, personal ads in newspapers helped single men search for wives in England. Video dating emerged in the 1980s. Match.com launched in 1995. 

And now, Tinder — which launched in 2012 — has made finding compatible partners online even easier. 

The app matches couples based on a preferred age range, gender identity or proximity — ranging from 1 to 100 miles away. With the help of five photos and a short bio, users can swipe right or left to indicate whether they want to match with — or pass on — a potential mate.

While the volume and variety of online dating services have modified prospective partners’ modes of communication, some experts say the standards and methods for finding “the one” have remained the same over time.

From signal, to message

Even as dating transitions to an online platform, experts say at least two components of courtship haven’t changed — showing interest and making an impression.

Matt Benson, a first-year physics and computer science student, never crossed paths with his future girlfriend of almost a year — Kayle Minear — when the two attended the same high school in the small town of Rock Island, Illinois.

Despite an unreciprocated swipe on Tinder, Benson added Minear on Snapchat. After a few failed messages, she finally agreed to a date.

“We had no mutual connection. I never would’ve thought before then that it would work and last,” Benson said. “[Without the technology], I never ever would’ve met her.”

For Benson, showing interest in Minear beyond a swipe is what dating experts call the transition from a “weak signal” to a “message.”

This concept precedes internet romance, said Ravi Bapna, a data analyst at the Carlson School of Management who researches online dating.

People send “weak signals” — swiping right on Tinder or smiling at someone — but “messages” constitute a tangible step forward, such as adding a potential partner on another app or suggesting a date.

With online dating, singles can plan their flirting strategy before sending interest signals to potential matches, Bapna said.

And while technological opportunities to find a partner have expanded, Sehoya Cotner — who studies the science of attraction and founded the “Evolution and Biology of Sex” course at the University — has a new hypothesis on patterns of dating that have been unchanged by the digital age.

Traditionally, humans use biological instincts such as scent and sight to judge attraction. Then they assess compatibility by comparing more abstract traits like religions and ideologies, Cotner said.

With online dating, users can skip pheromones and skim for matching political views.

Still, Cotner doesn’t advise daters to swap out the instinctual cues for a Snapchat streak.

“The animalistic stuff still comes into play after we’ve checked all the boxes,” she said.

‘What do we do that’s so traditional?’

While the concept of online dating is still seen as taboo by some, the standards for dating haven’t changed, experts say.“I definitely think there’s a stigma around apps,” said strategic communications sophomore Rachel Ball. “There’s this notion that they’re just for hookups, or they’re kind of dirty.”

Even today, Benson and Minear are not always truthful when people ask how they met. They often credit Minear’s sister with introducing them. LaPrairie and Baker tell people they were in the same psychology discussion section.

And until something serious comes of it, users often play off their swiping habits as entertainment. Pace University professor Aditi Paul, who researches online dating, said these jokes let people hold on to the fantasy of meeting someone serendipitously.

“If you want to tell your children how you met their father, you don’t want to say it was just a right swipe. Tinder robs that opportunity [for romance],” Paul said.

But others embrace their Tinder stories.

University graduate Miguel Rocha and his wife, Mindy, met on Tinder and say swiping is the new normal.

“What do we do that’s so traditional? You order clothes, buy beer and book tickets online,” Rocha said. “You do everything else on a phone and all of a sudden say you’re too good to find someone on a phone?”