Most people aren't trying to share fake news, but that's part of the problem: Nobody thinks it's their fault.

In a recent survey of 8,285 Americans, 90 percent of respondents thought they were better than the average person at spotting false news on social media.

Obviously, a lot of people were mistaken. When asked to distinguish between a series of false and accurate Facebook news headlines, three-quarters of the group scored lower than they thought they would.

Most people ranked themselves about 22 percentiles higher than their actual performance, but a significant chunk of the group was even further off the mark. In the survey, roughly one-fifth of respondents overrated their news judgment by more than 50 percent.

"Though Americans believe confusion caused by false news is extensive, relatively few indicate having seen or shared it," explains social psychologist Ben Lyons from the University of Utah.

"If people incorrectly see themselves as highly skilled at identifying false news, they may unwittingly be more likely to consume, believe, and share it, especially if it conforms to their worldview."

This is precisely what researchers found when they looked at what websites each respondent was visiting. The data was offered up freely to the authors from each person's laptop or desktop computer.

Analyzing the search history, it was clear those who were most overconfident in their news judgment spent more time frequenting untrustworthy websites. What's more, those who overestimated their fake news radar reported being more likely to share false content on social media, especially when it aligned with their beliefs.

"In all, these results paint a worrying picture," the authors conclude. "The individuals who are least equipped to identify false news content are also the least aware of their own limitations and, therefore, more susceptible to believing it and spreading it further."

If the authors are right, overconfidence could be a crucial factor in the spread of fake news. It's a classic case of the Dunning-Kruger effect, which is a cognitive bias where people who are bad at a task think they are good at it, and therefore don't see a need to improve.

It's a bias no one thinks they're actually guilty of, but most of us probably are at some point in our lives.

Even online, it seems, we can be similarly deluded. The results here suggest the vast majority of social media users are unable to recognize the shortcomings of their news judgment, and this means they are at risk of inadvertently consuming fake news.

"Many people are simply unaware of their own vulnerability to misinformation," the authors write.

"Targeting these overconfident individuals could be an important step toward reducing misinformation on social media sites, though how best to do so remains an open question."

The study was published in PNAS.