Fake news may be trickier for young internet users to spot than previously believed.

A new study from Stanford University found that even members of generations purported to be the most web-savvy of all time are often tripped up by deliberate misinformation online.

The researchers behind the report tested thousands of students ranging from middle schoolers to college kids on their ability to pinpoint obvious political biases, basic signs of credibility and sponsored content tags.

They found that the young people by and large failed their age-appropriate tests for news literacy.

"Many people assume that because young people are fluent in social media, they are equally perceptive about what they find there," Stanford education professor Sam Wineburg, the lead author of the report, said in a statement. "Our work shows the opposite to be true."

The findings come as the spread of intentionally false news online has dominated media discussion in the wake of a presidential election in which it seemed to hold more sway than ever on public opinion.

After several days of denying his platform was part of the problem, Facebook CEO Mark Zuckerberg recently rolled out a comprehensive plan to strengthen the social network's defenses against such stories that relies in large part on vigilant users identifying and reporting them.

But if even the most supposedly web-fluent users have trouble sorting out hoaxes and misleading sources — as the study indicates — it seems Facebook's strategy may not go far enough.

The authors of the study used a host of separate tests to determine their subjects' news judgment, each designed to fit students' respective academic levels. The material encompassed social media feeds, comment sections, blog posts, photographs and any other digital media with the potential to influence the students' outlook on a political issue.

In one test, middle schoolers were asked to differentiate between native ads — branded posts designed to camouflage with other content — and actual news articles on the Slatehomepage. Of the 203 students interviewed, more than 80 percent failed to notice the sponsored content marker.

That finding shouldn't come as too much of a surprise; several other studies have found that web surfers of all ages have trouble with this distinction.

Another test asked high school students to choose the more credible of two tweets — one from the verified Fox News account and another from a handle that closely resembled it. Three quarters failed to note the significance of Twitter's blue checkmark certification, and three in ten said the fake account seemed more legitimate because of its graphic design.

Around four in ten high schoolers also believed a thinly sourced photograph of wilted flowers on the photo-sharing site Imgur was strong evidence that the disaster at Japan's Fukishima Daiichi nuclear plant caused “nuclear birth defects” based on the headline alone. Less than a fifth gave responses that indicated "mastery" of the news value, according to the study's rubric.

Meanwhile, college students — a sample that encompassed attendees of highly selective schools like Stanford and big state universities — were expected to evaluate the validity of various websites with more nuance. Yet the study found that more than nine out of ten of respondents were unable to recognize a front website for a lobby group posing as a reputable news site, faring even worse than Advanced Placement high school students given the same test.

Overall, students consistently underperformed researchers' expectations in the vast majority of the tests.

"Young people’s ability to reason about the information on the Internet can be summed up in one word: bleak," the authors wrote in an introduction to the study.

Despite a growing number of courses now purporting to teach media literacy across different grade levels, it seems that tactics used to spread deliberately fake news and the blending of advertising with editorial content may be outpacing educators' abilities to warn students of them.

As big digital platforms like Facebook and Google crack down on the abundant fake news within each of their sites, the study suggests that lessons may be needed at a more fundamental level in order to effectively combat the problem.