MINNEAPOLIS (WCCO/CBS Local) — For parents who constantly chide their children to “grow up,” a new study on teens and adolescence is suggesting they’ll have to wait even longer. According to findings published in the journal, Child Development, today’s teens are putting off many of the common behaviors associated with moving into adulthood.

Compared to teens in the 70’s, 80’s, and 90’s, today’s adolescents, “are taking longer to engage in both the pleasures and the responsibilities of adulthood,” according to San Diego State University’s Jean Twenge. “The whole developmental pathway has slowed down,” the professor of psychology added. Twenge concludes that today’s 18-year-olds are living more like 15-year-olds did in previous generations.

The data for the massive survey was compiled over four decades from 1976 to 2016 and included over eight million teens. It found that teens from 2010 to 2016 were having sex, drinking, and holding a paid job at much lower rates than teens did 20 years ago. Among 8th graders, about half the number of younger teens had a job or tried alcohol compared to kids in the 1990’s.

Older teens (12th graders) are reportedly having even fewer milestone moments. Compared to older teens dating back to 1976, the number of kids dating, working, getting a driver’s license, or drinking was down nearly 20 percent in every category.

“I think if you ask any college professor, they’ll tell you students these days are woefully unprepared in basic life skills,” said NYU professor of child and adolescent psychiatry Yamalis Diaz. “It’s like going into the heavy lifting of adulthood without having exercised the necessary muscles,” Diaz added.

Professor Twenge, the study’s lead author, added that while there’s a positive to not experimenting with underage sex and drinking, the choices aren’t being born out of better decision-making.

“Our results show that it’s probably not that today’s teens are more virtuous, or more lazy—it’s just that they’re less likely to do adult things.”