by Jeroen van Baarat 3 Quarks Daily: In the chart-topping podcast The Rest is History, British historians Tom Holland and Dominic Sandbrook discuss key events from the past at great length and in sumptuous depth. I was listening to their fourth episode on the French Revolution when a detail caught my ear. Part of the reason the Revolution could occur, Tom and Dominic argued, is that a nasty opinion publique had taken hold in late-eighteenth-century Paris. Pamphlets filled with inflammatory rumors were sold by the tens of thousands and read aloud on street corners. Some of them spread fables about the alleged sexual escapades of the young queen Marie Antoinette, which eroded the authority of the monarchy and set the stage for its bloody demise.
It is all too reminiscent of public opinion today. In the recent Trump-Harris presidential debate, for instance, Trump alleged that Democrats were condoning post-birth abortions. “Her Vice-Presidential pick […] says execution after birth is OK,” Trump said. And later: The “former governor of Virginia said we put the baby aside and then we determine what we want to do with the baby.”
To those uninitiated in Republican propaganda, the comment must have sounded like yet another ridiculous falsehood made up on the fly by the former president. But as a political neuroscientist, I recognized it from five years ago. In 2019, I was a researcher at Brown University studying how the brains of political partisans color their perceptions (of an inauguration crowd, perhaps). 43 committed Democrats and Republicans watched political videos in our brain scanner. One of the videos we used was a PBS news segment on abortion, in which then-Virginia Governor Ralph Northam, a pediatrician and a Democrat, described what happens in the tragic scenario when a fetus is not viable outside the womb: resuscitation is attempted if the parents so desire. Despite numerous clarifications from Northam, this was gleefully interpreted by Republicans to mean that Democrats condone “legal infanticide”. The fact that Trump is still touting this conspiracy theory five years later speaks to its effectiveness at riling his base.
In our study, we discovered that neural processing of the PBS video was more similar between two people who had the same political orientation than across the aisle. Why? One reason is that our brains constantly link incoming information to knowledge stored in memory. So if you’ve heard this
this particular conspiracy theory before, the way your brain encodes Trump talking about it will be very different than for someone who is taken aback by the seemingly novel absurdity. This has important implications for repairing our polarized political landscape. Even if we could convince opposing partisans to consume the same information, like (approximately) unbiased news, they would interpret it differently depending on the “programming” they have received in the past. The rift of understanding is widened every time a conspiracy theory is rehearsed, like Trump did in the debate. People who spread these falsehoods, clearly, are not interested in uniting the nation.
This raises a critical question about conspiracy theories. After they have been released into the population, how long does it take for them to die out? A team of Italian researchers reported in 2022 that participants who strongly believed in a falsehood like “the moon landing was fake” in 2016 supported that belief less strongly in the 2020 follow-up, suggesting that a person may “recover” from being “infected” by a false idea. But the true power of conspiracy beliefs is not that they are kept alive by the same individuals, but rather that temporary believers pass them around, like a rock star crowd surfing on a crowd. By the time a “host” has recovered from the “virus”, it has already spread to many others.
The virus analogy goes a long way here. Just as the coronavirus was quicker to multiply than previous pandemics thanks to our improved global transportation systems, false beliefs like “COVID-19 vaccines cause autism” spread more swiftly thanks to our amazing global communication systems. When I was growing up, there was one guy in the town square waving his pamphlets about alien abductions and crop circles. Nowadays, this man has an account on Twitter or Truth Social and shares his notions with billions.
Even online, though, conspiracy beliefs only spread if they are infectious in themselves. What makes them so? Interestingly, conspiracy theories may be attractive because it is valuable to believe them. This is paradoxical, as a belief must usually be true to have value. The statement “Bus 60 does not run on Sundays” will only help you get around the city if it is correct. But conspiracy beliefs are very different in nature. They talk about stuff so far removed from our everyday existence—the goings-on of world leaders, moonwalkers, or queens in Versailles—that they carry no evidential value at all. Instead, they are valuable because they make us feel better (people in power suck!) or because they allow us to connect with others.
