While fake news is often bizarre, one of the stranger fake claims was that the Comet Ping Pong pizzeria was part of a child sex ring led by Hillary Clinton. This fake story made the real news when Edgar M. Welch allegedly armed himself and went to the pizzeria to investigate the story. This  investigation led to gunfire, although no one was injured. Mr. Welch surrendered peacefully to the police after finding no evidence of the sex ring.

Given that the story had been debunked by the New York Times, Snopes, and the Washington Post, it might be wondered why someone would believe such a claim. Laying aside the debunking, it might also be wondered why anyone would believe such a seemingly absurd claim.

Some might be tempted to dismiss people who believe fake news as fools or stupid, most likely while congratulating themselves on their own intellectual prowess. While there is no shortage of fools and everyone is stupid at least some of the time, the “people are stupid” explanation does not suffice. After all, intelligent people of all political stripes are fooled by fake news.

One reason why fake news of this sort convinces people is that it makes use of the influence of repetition. While people tend to be skeptical of odd or implausible claims when they first encounter them, there is a psychological tendency to believe claims that are heard multiple times, especially from multiple sources. While the Nazis did not invent this technique, they did show its effectiveness as a rhetorical tool. The technique of repetition is used more benignly by teachers trying to get people to memorize things. Not surprisingly, politicians and pundits also use this method under the label of “talking points.”

This psychological tendency presumably has some value. When people are honest, things that are repeated and come from multiple sources would generally be true (or at least not deceits). The repetition method also exploits a standard method of reasoning: checking with multiple sources for confirmation. However, such confirmation requires using reliable sources that do not share the same agenda. Getting multiple fake news sites reporting the same fake story creates pseudo-confirmation that creates an illusion of plausibility. The defense against this is, of course, to have diverse sources of news and preferably some with less ideological slant.  It is also useful to ask yourself this question: “although I have heard this many times, is there evidence it is true?”

Another reason fake news can be convincing is that the fake news sites often engage in active defense of their fake news. This includes using other fake sources to “confirm” their stories, attacks on the credibility of real news sources, and direct attacks on articles by real news sources that expose a fake news story. This defense creates the illusion that the fake news stories are real and that the real news stories are fake.

Some of these work through psychology: one might think that such a defense would only be mounted if there was truth worthy of the effort. Some appeal to reason: if the real news story exposing fake news is systematically torn down step by step, this creates the illusion of a reasoned argument disproving the claim that the fake story is fake. Attempts to discredit the sources also misuse legitimate critical assessment methods. The fake news sites accuse the real sources of news of being biased, bought and so on. These are legitimate concerns when assessing a source; the problem is not the method but the fact that the claims are also typically untrue.

Those who do not want to be duped can counter this fake news defense by the usual method of checking multiple, diverse and reliable sources. But this is increasingly difficult as fake news sites proliferate and grow more sophisticated.

A third reason that fake news can seem accurate is that it has supporters who use social media to defend the fake stories and attack the real news. Some of these people are honest in that they believe they are saying true things. Others are aware the news is fake. Some even create fake identities to make themselves appear credible. For example, one defender of Pizzagate identified himself as “Representative Steven Smith of the 15th District of Georgia.” Georgia has only 14 districts; but most people would not know this. All these supporters create the illusion of credibility, making it difficult for people to ferret out the truth. After all, most people expect other people to be honest and get basic facts right most of the time as this is a basic social agreement and a foundation of civilization. Fake news, among its other harms, is eroding this foundation.

The defense against this is to research the sources defending a news story. If the defenders are mostly fake themselves, this would indicate that the news story might be fake. However, fake defenders do not prove the story is fake and it is easy to imagine the tactic of using fake defenders to make people feel that a real news is fake. For example, a made up radical “liberal source” defending a story might be used to try to make conservatives feel that a real news story is fake.

A fourth reason that fake news can seem accurate is that the real news has been subject to sustained attacks, mostly from the political right in the United States. Republicans have made the claim that the media is liberally biased a stock talking point, which has no doubt influenced people. Trump took it even further, accusing the news of being terrible people and liars (ironically for reporting that his lies are lies). Given the sustained attack on news, it is no wonder that many people do not regard the real news as reliable. As such, the stories that debunk the fake news are typically rejected because they are the result of liberal bias. This does, of course, make use of a legitimate method of assessing sources: if a source is biased, then it loses credibility. The problem is that rather than being merely skeptical about the mainstream media, many people reject its claims uncritically because of the alleged bias. This is not a proper application of the method as the doubt needs to be proportional to the evidence of bias.

In regard to people believing in seemingly absurd claims, there are both good and bad reasons for this. One good reason is that there are enough cases of the seemingly absurd turning out to be true. In the case of Pizzagate, people hearing about it probably had stories about Jared Fogle and Bill Cosby in mind. They probably also heard stories about cases of real sex rings. Give this background, the idea that Hillary Clinton was tied to a sex-ring might seem to have some plausibility. However, the use of such background information should also be tempered by other background information, such as information about how unlikely it is that Hillary Clinton was running sex-ring out of the basement of a pizza place. That has no basement.

The bad reason is that people have a psychological tendency to believe what matches their ideology and existing opinions. So, people who already disliked Hillary Clinton would tend to find such stories appealing as they would feel true. Such psychological bias is hard to fight,  people take strong feelings as proof and often double down in the face of facts to the contrary. Defending against bias is probably the hardest method as it requires training and practice in being aware of how feelings are impacting the assessment of a claim and developing the ability to go into a “neutral” assessment mode.

Given that fake news is spreading like a plague, it is wise to develop defenses against it to avoid being duped, perhaps to the point where one is led to commit crimes because of lies.