Misinformation or fake news is not easy to spot on Facebook, according to a study which suggests that the social networking site muddies the waters between fact and fiction.
In the study, published on Tuesday in the journal Management Information Systems Quarterly, participants were fitted with a wireless electroencephalography (EEG) headset which tracked their brain activity during exercise.
They were asked to read political news headlines presented as they would appear in a Facebook feed and determine their credibility.
The participants assessed only 44 per cent correctly, overwhelmingly selecting headlines that aligned with their own political beliefs as true, the researchers said.
"We all believe that we are better than the average person at detecting fake news, but that's simply not possible," said lead author Patricia Moravec, an assistant professor at The University of Texas at Austin in the US.
"The environment of social media and our own biases make us all much worse than we think," Moravec said in a statement.
The researchers worked with 80 social media-proficient undergraduate students who first answered 10 questions about their own political beliefs.
Each participant was then fitted with an EEG headset. The students were asked to read 50 political news headlines presented as they would appear in a Facebook feed and assess their credibility.
Forty of the headlines were evenly divided between true and false, with 10 headlines that were clearly true included as controls.
The researchers randomly assigned fake news flags among the 40 non-control headlines to see what effect they would have on the participants' responses.
In 2016, Facebook incorporated fact-checking into its platform and began flagging certain news articles by noting that an article was "disputed by third-party fact checkers."
The students rated each headline's believability, credibility and truthfulness.
When the students read headlines which supported their beliefs, but were flagged as false, they spent more time and showed significantly more activity in their frontal cortices -- the brain area associated with arousal, memory access and consciousness.
These reactions of discomfort indicated cognitive dissonance when headlines supporting their beliefs were marked as untrue.
However, this dissonance was not enough to make participants change their minds, the researchers found.
They overwhelmingly said that headlines conforming with their preexisting beliefs were true, regardless of whether they were flagged as potentially fake, according to the study.
The flag did not change their initial response to the headline, even if it did make them pause a moment longer and study it a bit more carefully.
The researchers found that political affiliation made no difference in their ability to determine what was true or false.
They noted that Facebook muddies the waters between fact and fiction.
The experiment showed that social media users are highly subject to confirmation bias, the unintentional tendency to gravitate towards and process information that is consistent with existing beliefs, Moravec said.
This can result in decision-making that ignores information which is inconsistent with those beliefs, she said.