Today’s teenagers don’t seem to care much about hitting the open road, scoring a six-pack with a fake ID, or asking their peers out on dates.

According to a new study from the psychologists Jean Twenge and Heejung Park, teenagers instead prefer to sit at home, avoid drugs and alcohol, and scroll through a litany of social-media apps.

The study, published in the journal Child Development, analyzed survey responses from 8.3 million teenagers between 1976 and 2016. Overwhelmingly, today’s teens were found to be less likely to drive, work for pay, go on dates, have sex, or go out without their parents.

By the early 2010s, the researchers wrote, 12th-graders were going out less often than eighth-graders did in the early 1990s and going on dates about as often as 10th-graders did in the early 1990s. Kids were also trying alcohol later and having sex far less often: About 54% of high-school students in 1991 reported having had sex, while only 41% did in the early 2010s.

“This isn’t just about parenting,” Twenge told Business Insider. “It’s also about teens themselves, and the economy, and fertility rates, and people living longer.”

Of course, since the study's conclusions are based on personal survey responses, the findings may not apply broadly to all of Generation Z, generally defined as people born in the early 1990s to mid-2000s. There are also bound to be members of the generation for whom the traits don't apply, as with any demographic study.

But Twenge chalked the findings up to an overall shift in the way society has operated. She is the author of "iGen: Why Today's Super-Connected Kids are Growing Up Less Rebellious, More Tolerant, Less Happy - and Completely Unprepared for Adulthood," which explores the conditions in which today's young people are being raised. Contrary to popular belief, Twenge said, teens aren't lazy or square, but are a product of their environment, like every other generation.

In the mid-20th century, she said, people adopted what evolutionary psychologists call a "fast-life strategy." Life spans were shorter and work was more imperative, so kids grew up relatively quickly without as much parental supervision. By 2000, though, the US had taken up a "slow-life strategy" - people were living longer, resources were more abundant, and parents started raising their kids to stay kids longer.

Because there seems to be less of a need for modern teens to become adults, Twenge and Park's research suggests that today's 18-year-old more closely resembles a 15-year-old of the 1970s or '80s.

However, one of the most disturbing characteristics of Generation Z, or "iGen" in Twenge's parlance, is a suicide rate that has surpassed the homicide rate in that age group. Twenge thinks smartphone use may play a crucial role in contributing to that. Gen Z is the first generation to be raised according to this slow-life strategy amid the prominence of smartphones. (Its members, after all, are the first to have no concept of life without the internet.) Instead of working or playing outside, teens are more likely to feel isolated and tethered to their devices.

"Today's teens may go to fewer parties and spend less time together in person, but when they do congregate, they document their hangouts relentlessly - on Snapchat, Instagram, Facebook," Twenge wrote recently in The Atlantic. "Those not invited to come along are keenly aware of it."

But getting rid of smartphones shouldn't be parents' first goal if they want to safeguard their kids' mental health - according to the study's findings, Twenge said, it should be encouraging independence. If kids are more concerned with working or getting involved in their community, they'll naturally have less idle time to fill with their smartphone.

At the same time, not all of Gen Z's traits are problems that need to be solved, she said, like the lower incidences of drinking and sex.

"Let's have those go to zero," Twenge said. "That would be just fine."