杏吧原创

IN 1951 at Swarthmore College, Pennsylvania, social psychologist Solomon Asch staged a telling experiment on groups of eight students. He showed them three lines of different lengths and asked them which one matched a fourth line. The answer was obvious.

But seven of the students were in fact actors. When they went first and gave the wrong answer, the eighth participant 鈥� the real one 鈥� was much more likely to do the same. This became known as the 鈥渃onformity experiment鈥� 鈥� proof of the human tendency to be gullible.

Throughout history, people have often been portrayed as credulous. Preachers see the trait in those who believe in gods other than theirs. Atheists bemoan the credulity of all believers. Conservatives see it in those who revolt. Leftists say it explains why more people don鈥檛.

In Not Born Yesterday, cognitive psychologist Hugo Mercier argues that actually we aren鈥檛 easily fooled, wielding psychological, biological and historical evidence to make the case that humans are hardwired to work out who and what to believe.

While the complexity of our communication makes us more adaptable, it also means staying open to beneficial messages and alert to harmful ones. That is why, Mercier says, we have 鈥渙pen vigilance鈥� cognitive mechanisms, the most basic of which he calls plausibility checking. This involves comparing new information with existing beliefs, drawing on the past reliability of sources and checking new messages against intuitions.

Mercier bolsters his case with examples from comparative biology. For example, why do fit Thomson鈥檚 gazelles jump up and down rather than run when they see predatory wild dogs? How does this deter the dogs from chasing?

鈥淔ake news can spread smears about politicians, but only among those who dislike its targets鈥�

No one knows for sure 鈥� it might be a form of deception. But Mercier argues that dishonesty (in prey or predator) would require gullibility to endure, and the need for that gullibility to confer benefits means that it can鈥檛 survive as a stable trait.

History backs Mercier up. In Nazi Germany, anti-Semitic propaganda was only effective in areas with high levels of existing prejudice against Jewish people. He also cites research on US political campaigns that concludes that their impact on voters is negligible. Studies show that fake news can spread smears about politicians, but only among those who already dislike its targets.

But what about creationism or anti-vax beliefs? And surely the open vigilance mechanisms of those who fall for 9/11 or moon landing conspiracy theories are failing them? Conspiracy beliefs are, perhaps, where Mercier is at his weakest, as he argues these aren鈥檛 down to gullibility but occur as a result of plausibility checking operating on 鈥減oor material鈥�.

For Mercier, conspiracy theories are held as reflective beliefs that can remain insulated from our other beliefs and actions. These contrast with intuitive beliefs, from which we freely draw inferences and use to ground our actions. Couldn鈥檛 the same be said of those who accept climate change science yet still fly or eat meat? Maybe it isn鈥檛 so binary.

Despite this, Mercier鈥檚 insights may help us learn more about why we can get things wrong. At the risk of being seen as credulous, I鈥檇 say he makes a strong case for gullibility being a far less prevalent and important trait than we thought.

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