In today’s world, it can sometimes be hard to distinguish fact from fiction, to know what is real and what is merely claimed to be real.
While disinformation has a long history, our current world of fake news, alternative facts and social media falsehoods appears to suffer particularly from a crisis of truth.
The issue is especially critical given that the world is grappling with a global pandemic and “anti-vax” sentiment could hamper efforts to achieve mass immunity.
A new Abu Dhabi study looking at how the brain processes information presented as facts versus information presented as possibilities is therefore particularly timely.
It highlighted differences in how our minds deal with the two types of information, and could lead to insights about how we process things we are told even when we know the source is untrustworthy.
It is no surprise, then, that the work has generated quite a buzz.
“The reason this study is attracting a lot of attention is because we have so much misinformation in our environment. There are a lot of sources we don’t trust,” said Prof Liina Pylkkanen, co-director of the neuroscience of language laboratory at New York University Abu Dhabi and the study’s senior author.
Published in the journal eNeuro, the research involved presenting statements to volunteers and analysing the subsequent activity in their brain.
The researchers were interested in differences in the neural response when the person read sentences that included moda” words expressing uncertainty, such as might or may, compared with factual sentences without these words.
A simple example involved could be something such as, “there is a vulture flying overhead” versus “there might be a vulture flying overhead”.
Coming up with the sentences was complex and time-consuming, because the facts and possibilities phrases had to match exactly except for the modal words.
This part of the study took the researchers a year to complete.
During experimental work at NYU Abu Dhabi and at NYU’s New York campus, a technique called magnetocephalography (MEG) was used so that as participants read the sentences, sensors recorded magnetic fields generated by the brain’s electrical activity.
While some colleagues had suggested that the contrasts between modal and non-modal sentences were so subtle that no difference in electrical activity was likely be found, a clear pattern emerged – but in the opposite direction to the one the researchers expected.
When subjects were played sentences that expressed facts, their brains responded more strongly, with a spike in electrical activity, than when sentences expressing possibility were played.
“Our goal was really to try to isolate neural correlates of the possibilities-type language, but it turns out the factual language elicits a much more robust brain signal, so we actually discovered something different. Interesting, but not what we were looking for originally,” Prof Pylkkanen said.
Another key finding, said Maxime Tulling, a PhD student at NYU’s Department of Linguistics and the paper’s first author, was that the brain reacted very quickly.
“About 200 to 300 milliseconds after this contrast is presented, [the brain] seems to be doing something extra, it seems to be extra activated for facts versus possibilities,” she said.
This speed is fast enough that the brain most likely assimilates the information unconsciously, so it is happening as part of automatic language processing.
Some people jumped to the conclusion that the brain’s stronger responses to factual language indicate that, if we want to convince others, we are better off conveying information as fact rather than possibility.
Dr Ailís Cournane, an assistant professor in NYU’s Department of Linguistics and another of the paper’s authors, would, however, like people to express uncertainty where it exists. She noted that the language tools to express this exist in every language.
“There definitely is this push for people not to hedge and to speak more in assertions and in unmodalised language, but that doesn’t make sense to me, because it’s about what you want to say and how certain you are,” she said.
“I think we need to just be honest about that and not police our language like that, as very often marking uncertainty is important and truthful.”
Prof Pylkkanen suggested the findings of the study offered people important knowledge about what happens in their brain when they heard something they thought was fact.
“Obviously, we want to make disinformation and fake news go away, so maybe just some increased awareness from a neuroscience perspective about how our brains actually respond to facts versus things that aren’t facts is important, and highlights the danger of packaging something as fact when it’s not fact,” she said.
The findings also suggest very topical follow-up work that could shed light on how people may be susceptible to unreliable sources of information.
For example, Prof Pylkkanen suggested it would be interesting to look at how the brain reacted when people were presented with factual information from a source they knew was untrustworthy. In the current study, the sentences expressing facts or possibilities have no such context.
If the brain reacted in the same way to factual information even though the source was untrustworthy, it would suggest, Prof Pylkkanen said, that there was “a very early neural level” at which the brain responded. It would also highlight the risks created when fake information is presented as fact.
“There’s fake news that catches on. So there’s the question: how does the brain deal with factual language when it’s coming from a source that’s not reliable, not being truthful,” Dr Cournane said.