Fake news leaves a lasting impression on the less smart

One reason why fake news is dangerous is that we don't like giving up reassuring certainties, and once we have a take on things, it colours further information – hence the seeming bulletproof nature of conspiracy theories and partisan political hatreds. But new research in Intelligence suggests this is truer for some people than others. For mentally sharp people, the results suggest it's relatively easy to jettison an outdated perspective, while for those of lower cognitive ability, the dregs remain.

Jonas De keersmaecker and Arne Roets from the University of Ghent recruited 390 participants from an online pool, and asked them to read a description of a nurse named Nathalie. For some participants this description ended with a damning revelation: Nathalie had been stealing drugs from the hospital and selling them to buy designer clothes. Understandably, these participants subsequently rated Nathalie negatively, as less trustworthy, sincere, warm, and hostile, compared to a control group who hadn't been told about her misdeeds.

All participants then completed a short cognitive ability test, measuring their vocabulary knowledge of ten words. Next, those told about Nathalie's stealing were presented with a plot twist: the accusations were entirely untrue (both accounts of Nathalie were from a "God's-eye perspective", stated as fact, with no reference to supporting evidence).

Next, the participants reviewed the information about Nathalie (with the stealing information clearly crossed out, if they had seen it earlier) and they rated her again on the various characteristics. Overall, those privy to the earlier false stealing claims now gave her much more positive ratings, similar to the control participants. But within the false accusations group, De keersmaecker and Roets found that those with below-average cognitive ability (by at least one standard deviation) continued to give Nathalie more negative ratings, than their high-ability counterparts and the control group.

The sustained negative ratings of Nathalie given by those with lower cognitive ability were only about ten points more negative than those given by the other groups, on average. This is compared to the average, 50-point positive jump in ratings seen among the false accusation group as a whole once they learned the claims had been retracted. But the researchers point out that the 10-point gap shows that for the lower cognitive ability participants, a residue of the old accusation remained, even though it was only "out there" for a short time, and unambiguously retracted. This effect would present a problem in the real world where grossly fake news of every flavour can be rapidly shared and spread – even when it only outpaces a correction by minutes, it could still leave a lasting impact on some people.

It's not clear at this stage exactly the role that cognitive ability has – for example, whether it's directly involved in the correction of false beliefs and/or if it correlates with other traits that might be relevant. This is important because cognitive ability itself is hard to improve whereas associated skills like critical thinking are more trainable. We do know that cognitive ability was still relevant even after the researchers factored out obvious confounds like the personality traits of "need for closure" and authoritarianism, both of which are associated with lower cognitive ability and related to a dislike of ambiguity.

It would be useful for research to use a more refined measure of cognitive ability than the one used. Another limitation of the current research is that no evidence was given to justify either the initial or revised claims about Nathalie (of course this is exactly how many of us encounter claims on social media and elsewhere). Future studies could examine people's ability to interpret fake, biased or otherwise dubious evidence.

There is increasing attention on how to help people tackle fake news on first contact – such as this BBC initiative, which involved mentoring school pupils on how to spot fake news — and this new study reinforces the value of such tactics. The message is that where possible, we should prevent stubborn false ideas from taking root: it may be harder than we realise to shift them once they have.