One day, a well-dressed stranger approached Hugo Mercier as he was walking back from university. The stranger told Mercier he was a doctor running late for an urgent appointment, but had forgotten his wallet at home and desperately needed 20 euros for a taxi. Mercier gave the doctor the money in exchange for a business card with a phone number, which he could call to get his money back. But when he did, no one picked up. 

In his best-selling 2020 book Not Born Yesterday: The Science of Who We Trust and What We Believe, Mercier asks how he – a cognitive scientist with a postdoc and a teaching post at the École normale supérieure in Paris – could have fallen for such an obvious scam. The answer, he thinks, has less to do with the skill of the scammer than with his own preconceived notions of who could and couldn’t be trusted. “If you accept the premise that someone is who they say they are,” he writes, “a number of actions follow logically: had that person been a real doctor, I should have been able to trust him with the money.” 

Mercier’s experience is hardly unique. According to the Federal Trade Commission, people lost $10 billion to scams in 2023 in the United States alone – the “highest ever in losses reported.” The majority of scams unsurprisingly take place on the internet, where scammers can more easily assume different, more trustworthy identities. But scammers aren’t the only type of deceivers thriving in the online world. Equally concerning is the flood of misinformation being spread by politicians and conspiracy theorists – misinformation that, according to countless headlines, threatens the future of democracy itself. 

Does it? Mercier isn’t so sure. While other experts sound the alarm bells, Not Born Yesterday argues that much of the discourse surrounding the dangers of misinformation and the people that spread it actually goes against our understanding of evolutionary psychology, which posits that people are actually far more skeptical than they are given credit for. 

“We aren’t gullible,” its thesis claims, “by default we veer on the side of being resistant to new ideas. In the absence of the right cues, we reject messages that don’t fit with our preconceived views or preexisting plans. To persuade us otherwise takes long-established, carefully maintained trust, clearly demonstrated expertise, and sound arguments.”

Mercier makes the contrarian case that misinformation isn’t as large of a threat as it’s made out to be. At least, not when compared to our own trust issues.

Rethinking misinformation

Although Not Born Yesterday was met with a fair share of criticism upon its publication, several studies have since come out in support of Mercier’s argument. 

“A recent study measured the efficacy of television advertising,” Mercier tells Freethink over Zoom. “They looked at markets that were very similar, for example across two US states, and found that, on average, if a company doubles their advertising budget, they increase sales by one percent, which is pretty small.”

He compares this to another study published during the coronavirus pandemic:

“When the first wave of vaccinations rolled out in France, 80% of the French population was reported to be hesitant to get vaccinated. However, when people could see through their own experience, their social networks, and the media that the vaccines were working, and that there was no danger from them, the opinion flipped: 80% were now in support of the vaccines and willing to take them.”

Together, these studies point to the same conclusion Mercier reaches in his book: that people are difficult to persuade and selective about what information they accept as trustworthy. “I’m not claiming people are impossible to influence,” he stresses, “but that it’s difficult to make them change their minds about something.” In order for information to influence their opinions or beliefs, it has to come from a source they regard as friendly and reliable.

Discourse of misinformation often presents people as gullible, with no shortage of articles describing people easily falling down conspiracy rabbit holes and losing touch with reality. But this idea contrasts, in Mercier’s view, with the demands of the environment in which our species evolved – a world of life-threatening competition between tribes where outsiders were unequivocally treated with mistrust.

Paradoxically, these same survival mechanisms might explain why the efficacy and danger of misinformation are now being overestimated in the present. “Let’s say you’re a Democrat and you see a lot of Republicans agree on something you think is wrong,” Mercier explains. “While it’s tempting to think that they all acquired misinformation from the same place, like Fox News, the truth is that they came to the same conclusion rather independently.”

“People,” he argues, “have used this deeply-rooted natural bias towards out-groups to crack down on misinformation in various guises even when, as far as I can tell, misinformation itself has not done a lot of harm so far. In fact, 80 to 90% of misinformation online is consumed by hardcore supporters of one political side or the other, and these are people who have already made up their minds – they have not been actively influenced by the misinformation they are consuming.”

The idea that people are hard to influence is not entirely reassuring, however.

Not Born Yesterday suggests that the study of misinformation should pay less attention to the quality of misinformation itself – which is more often than not irrelevant – and more on our own lack of trust. The issue, in other words, isn’t that we change our minds on certain topics too quickly and easily, but rather all too rarely.

“The main effect of the mismatch between the way our brains evolved and the environment in which we find ourselves today is precisely that we don’t accept enough new information,” Mercier explains.

“Most of the factually inaccurate beliefs people have – the COVID vaccine is going to kill you, the US election was stolen – 99% of us have been exposed to correct, contradictory information on at least one occasion, and rejected it. We’re not equipped to figure out by ourselves who is competent, which sources we can trust. We resort to a state of cautious skepticism and do not change our minds even when we should.”

The truth about social media

Just as Mercier disagrees with the notion that misinformation is highly effective, so too does he disagree with the claim that misinformation has become more prevalent and dangerous due to the rise of social media.

Of the oft-repeated claim that social media platforms have created “echo chambers,” he says, “My understanding of research on the topic is that the tendency we have to surround ourselves with people like us predates, and is not related to, internet or social media. We stick to friends and colleagues who are like us because we don’t want to be fighting constantly. This also applies to print media: if you’re a Democrat, you are going to read the New York Times rather than right-leaning newspapers and vice versa.”

Mercier agrees that social media contributes to political polarization and civil unrest, but not because it separates and cuts off dialogue between people with different political beliefs. “It is plausible social media has negative consequences because it does the opposite: exposing us to more information from the other side.”

The problem is that, due to the way social media algorithms work, this exposure is almost always asymmetric, meaning the average Democrat isn’t exposed to the average Republican but just those whose posts get the highest engagement. Often, those are the most extreme of their group, garnering tons of views and likes through provocation.

“It’s not that you aren’t exposed to Republicans at all. It’s that the Republicans you are exposed to are non-representative of mainstream Republicans, which could explain the political polarization we are seeing in the US today. People on one side of the political spectrum have a completely distorted view of the other end. If social media is making things worse, it’s not by stopping us from viewing the other side altogether, but only exposing us to the worst of the other side.”

Mercier believes the best way to fight polarization in the US isn’t to fight the spread of “misinformation,” per se, but change the social media algorithms that determine online exposure to – and, subsequently, the level of trust in – both sides of the political spectrum.

This includes both individuals and media outlets. “If we look at polling of people’s trust in the media,” Mercier notes, “there has been an incredibly dramatic fall in recent years. Instead of telling people to put more faith in the media, mainstream media should do more to present itself as trustworthy. And while it’s generally more trustworthy than people give it credit for, there’s always room for improvement.” 

“Mainstream media should do more to present itself as trustworthy.”

The same, for the record, goes for government agencies:

“A good predictor of the popularity of conspiracy theories is how much people can trust the government. The less people trust their governments, the more likely they are to believe in conspiracy theories. If you want people to trust you more, you have to try to be more trustworthy.”