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When you see an article with tens of thousands of retweets and an exaggerated headline that you don't agree with, it's easy to blame fake news. And while it might seem like nothing more than a meme, fake news is a real thing.

Misinformation spreads across the Internet like wildfire, and might even spread more quickly than real news. But why? Well, it all comes down to human psychology and how our brains deal with the new information.

Scientists have been studying the cognitive basis of believing false information for a long time. Studies going back to the 1970s have looked at how people view new information that goes against things that they've already been told. For example, in one 1975 study, high school and college students were asked to compare two suicide notes and identify the real one.

Most students did okay — they could sometimes identify the real note, but not all the time. But then some students were told that they were either really good or really bad at the task. Later, the researchers revealed that they lied and clarified that, really, everyone just did okay.

But students still thought that they were better or worse at the task than they actually were — the lies stuck with them. Along with other studies on everything from economic decision-making to medical information, all this research shows that humans aren't very logical. Even when we're given information that should adjust our beliefs, like learning something is a straight-up lie, it's hard for us to let go of how we initially feel about a person or a situation.

A possible factor in this is confirmation bias: we tend to be more convinced by ideas that support our beliefs, while opposing information doesn't seem so trustworthy. This is partially because of what psychologists call motivated reasoning. Basically, we're motivated to reach conclusions that we want to reach.

Like, if you're diagnosed with a nasty health condition, you're more motivated to find reasons why the test might be wrong than reasons to agree with it. It's better for you if you're not actually sick. On top of that, we tend to believe that our views are correct and other people are wrong, especially if their views disagree with ours.

This is called naive realism and makes it hard for us to separate facts and opinions. These psychological patterns show that our brains can be pretty easily led astray by misinformation. But this doesn't completely explain how and why fake news goes viral.

Part of the problem might be the fact that, according to a pretty comprehensive survey, over half of U. S. adults get at least some news from social media. There's so much information, and it can be hard to tell which sources are credible.

Like, a blog post about how coconut water makes you live longer probably isn't fact-checked like a scientific press release, but it might make for a viral tweet. And social media companies are motivated to promote whatever gets the most traffic and attention, which isn't necessarily what's true. This could also play into the illusory truth effect: the idea that we tend to believe information we're exposed to repeatedly, whether or not it's true.

A 2016 study at Yale, shared on the open-access platform SSRN, tested for this effect. They exposed participants to both real and fake news headlines and then distracted them with demographic questions about themselves. Later in the same session or after a week, participants were presented with more headlines.

And they rated stories they'd seen before as more accurate — even pretty implausible ones. For example, one of the fake headlines was about a nationwide ban on all TV shows with gay relationships. This effect kind of makes sense — when a whole bunch of people keep talking about the same story, it seems to have more credibility than if one random dude was shouting it on a street corner.

But these headlines have to be shared for a reason. And fake news actually seems to be shared more than real news. A study published in Science in March 2018 looked at how fake news is spread using social media, with a massive longitudinal data set following Twitter stories from 2006 through 2017.

It included over 125,000 stories shared by around 3 million users, and found that fake news spreads farther and faster than the truth. This was especially true for political news, compared to other categories like scientific or economic news. These results go along with data from Buzzfeed in 2016, showing that false stories were shared on Facebook more than true stories during the few months leading up to the presidential election that year.

And, importantly, this Science study found that fake stories are being shared by real people — not by bot software. So it's not as simple as blaming Twitter bots for spreading misinformation. The authors think that the novelty of false headlines could partially explain this trend.

Maybe so many people are retweeting fake news because it's more surprising and interesting than real news. In other psychology studies on viral content, the stories that people were more likely to share made them more emotionally charged — either positively or negatively. So this idea fits with that pattern.

Now, all of this is pretty...intense. So how can we resist the influence of false news if it's everywhere and spreads so easily? Well, one idea is to tag headlines with warnings if third-party fact checkers have found them to be dubious.

In the 2016 Yale study, this significantly reduced the chances that a headline was perceived as accurate, even if participants saw it a couple times. Another tactic is to look more carefully at news sources. It's easy to lean into confirmation bias when you're arguing with your Aunt Sue on.

Facebook and looking up sources to back up what you already think. But you can dig deeper into news outlets and authors to understand things like what biases they might have or how they did their research, and think about sources more critically. And finally, when you see a surprising headline, take a second to reflect on it before you click on the “share,” “ retweet,” “show all your friends” buttons.

Shocking stories might seem important to amplify, but they're not necessarily true. The Internet is a tricky place to navigate these days, I am aware of this, but there are ways to handle misinformation. And if enough people and companies keep working on this kind of transparency and critical thinking, it might help to turn the tide.

Thanks for watching this episode of SciShow, which is produced by Complexly, a group of people who believe the more we learn about the world, the better we are at being humans. If you want to learn even more about how media affects how we think and act, we would like you to check out our show, Crash Course Media Literacy, at youtube.com/crashcourse. [♪ OUTRO ].