Follow CBSMIAMI.COM: Facebook | Twitter

MIAMI (CBSMiami) — A new study in the journal Child Development shows teenagers aren’t growing up as fast as they used to.

READ MORE: North Miami Beach PD Needs Help Locating 15-Year-old Jeimy Henrriquez

Researchers looked at how often today’s adolescents engaged in adult activities including drinking, working, driving and having sex compared to teens of decades past.

Compared to teens from the 70s, 80s and 90s, today’s teens are taking longer to become involved in adult responsibilities and pleasures.

READ MORE: Former US Rep. Carrie Meek Passes Away At 95

The study is based on 40 years of survey data and found the slowing of teen development matches a well-documented slowing of young adult development which leads to people in their early 20s often acting more like teens and young teens often action more like children.

The shifts are seen in all economic groups and all parts of the country.

So what’s the reason? The internet, according to the study authors.

MORE NEWS: Officer Injured, Suspect Dead Following Coral Gables Police-Involved Shooting

They say the time teens are spending online may be behind the trend because kids are glued to TV screens instead of out driving and dating.