There used to be a time when any self-respecting teenager would not be seen with the parents on an outing. You cringed and pleaded school homework rather than to be taken on any family trip. Your bedroom was your private kingdom and the day that you’re going to leave home in the beat old VW to tackle life on your own terms couldn’t come soon enough.

Not so for today’s teenagers.

According to a new study by researchers at San Diego State University and Bryn Mawr College, 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 US teenagers, aged 13 – 19, 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 than previous generations.

“The developmental trajectory of adolescence has slowed, with teens growing up more slowly than they used to,” explains Jean M. Twenge, professor of psychology at San Diego State University and the lead author on the study.

“In terms of adult activities, 18-year-olds now look like 15-year-olds once did.”

Mid- to -late teens are missing all the classic milestones of adulthood that indicate growing independence like going out to earn your own money, going out with friends, driving, dating, having sex, and drinking alcohol.

The smartphone phenomenon

Instead of going out, teenagers are socializing on their smartphones from the safety of their homes. Although the researchers don’t blame smartphones for the late development of today’s teenagers, smartphone use is seen as at least part of the problem.

Here’s a disturbing give-away:

In a piece Twenge wrote for The Atlantic she quotes a teenager she spoke to: “She told me she’d spent most of the summer hanging out alone in her room with her phone. That’s just the way her generation is, she said.”

Then the minor said: “We didn’t have a choice to know any life without iPads or iPhones. I think we like our phones more than we like actual people.”

Twenge is the author of Generation Me,” and she has released a new book on the generation born after 1995 called iGen: Why Today’s Super-Connected Kids are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood.

A most disturbing finding

Being cloistered in their bedrooms, scrolling through social media feeds, teenagers are physically safer than previous generations, but they are physiologically less safe. The more time teens spend looking at screens, the more likely they are to report symptoms of depression.

“Psychologically, the generation born after 1995 are more vulnerable than Millennials were: Rates of teen depression and suicide have skyrocketed since 2011. It’s not an exaggeration to describe iGen as being on the brink of the worst mental-health crisis in decades. Much of this deterioration can be traced to their phones,” writes Twenge.

However, Twenge says taking the phones away is not the answer. Rather, parents should encourage independence like a job or getting involved in their communities.