The study shows how ubiquitous certain technologies have become in just a few years.
Now 95 percent of teens say they either have a smartphone or access to one. That number is up from 73 percent the last time Pew conducted the poll.
And 45 percent of those polled say they use the internet “almost constantly,” which has increased more than 20 percent.
Pew last surveyed American teens’ use of social media in 2015, and the new study shows some changes in the platforms they use.
For one, Facebook is no longer the dominant social media platform for teens. In the last survey, 71 percent said they used Facebook, with 52 percent using Instagram, and 41 percent using Snapchat.
The latter two platforms have seen big increases in their teen user bases, while Facebook has declined by 20 percent.
Teens use Twitter and Tumblr at around the same rates they reported in 2015, the survey found.
About a third of those surveyed said they used Snapchat and YouTube most often, while only 10 percent said the same of Facebook. Even fewer reported Twitter, Reddit and Tumblr as their most-visited site.
There does not appear to be a clear consensus about how they believe social media affects them. The largest share of those surveyed – 45 percent – said that the effect of social media is neither positive nor negative.
Of the 24 percent who reported that social media had a mostly negative effect, their top reasons included bullying/rumor spreading, lack of in-person contact and unrealistic views of others’ lives.
“I feel that social media can make people my age feel less lonely or alone,” one 15-year-old girl said. “It creates a space where you can interact with people.”
Income levels are also instructive in the survey. While smartphones proliferate across gender, race and class, teens from lower income families tend to have less access to home computers.
And people from lower socioeconomic backgrounds use Facebook more than those from families with higher incomes, the study found.
The researchers interviewed more than 1,000 parents from randomly selected households with teenagers between the ages of 13 and 17 and almost 750 teens for the survey between March and April of this year.
There is still no scientific consensus about how smartphones affect developing teenage brains, but recent research has raised alarm about possible negative effects.
A 2016 UCLA study showed that teens’ brains showed the same sort of electrical activity related to the “reward” of eating chocolate or winning money when they saw their social media posts being “liked.”
And a study published earlier this year in Nature Communications concluded that teens’ heightened sensitivity to acceptance and rejection “may make them specifically reactive to emotion-arousing media,” and that neuroscientific developments could help address some of the associated issues.