ᴡʜʏ ᴘᴇᴏᴘʟᴇ ʙᴇʟɪᴇᴠᴇ ɪɴ ᴄᴏɴsᴘɪʀᴀᴄʏ ᴛʜᴇᴏʀɪᴇs, ᴇxᴘʟᴀɪɴᴇᴅ ʙʏ sᴄɪᴇɴᴄᴇ

I’m sitting on a train when a group of football fans streams on. Fresh from the game – their team has clearly won – they occupy the empty seats around me. One picks up a discarded newspaper and chuckles derisively as she reads about the latest “alternative facts” peddled by Donald Trump.
The others soon chip in with their thoughts on the US president’s fondness for conspiracy theories. The chatter quickly turns to other conspiracies and I enjoy eavesdropping while the group brutally mock flat Earthers, chemtrails memes and Gwyneth Paltrow’s latest idea.
Then there’s a lull in the conversation, and someone takes it as an opportunity to pipe in with: “That stuff might be nonsense, but don’t try and tell me you can trust everything the mainstream feeds us! Take the moon landings, they were obviously faked and not even very well. I read this blog the other day that pointed out there aren’t even stars in any of the pictures!”
To my amazement, the group joins in with other “evidence” supporting the moon landing hoax: inconsistent shadows in photographs, a fluttering flag when there’s no atmosphere on the moon, how Neil Armstrong was filmed walking on to the surface when no-one was there to hold the camera.
A minute ago they seemed like rational people capable of assessing evidence and coming to a logical conclusion. But now things are taking a turn down the crackpot alley. So I take a deep breath and decide to chip in.
“Actually all that can be explained quite easily … ”
They turn to me aghast that a stranger would dare to butt into their conversation. I continue undeterred, hitting them with a barrage of facts and rational explanations.
“The flag didn’t flutter in the wind, it just moved as Buzz Aldrin planted it! Photos were taken during lunar daytime – and obviously, you can’t see the stars during the day. The weird shadows are because of the very wide-angle lenses they used which distort the photos. And nobody took the footage of Neil descending the ladder. There was a camera mounted on the outside of the lunar module which filmed him making his giant leap. If that isn’t enough then the final clinching proof comes from the Lunar Reconnaissance Orbiter’s photos of the landing sites where you can clearly see the tracks that the astronauts made as they wandered around the surface.
“Nailed it!” I think to myself.
But it appears my listeners are far from convinced. They turn on me, producing more and more ridiculous claims. Stanley Kubrick filmed the lot, key personnel have died in mysterious ways, and so on …
The train pulls up in a station, it isn’t my stop but I take the opportunity to make an exit anyway. As I sheepishly mind the gap I wonder why my facts failed so badly to change their minds.
The simple answer is that facts and rational arguments really aren’t very good at altering people’s beliefs. That’s because our rational brains are fitted with not-so-evolved evolutionary hard wiring. One of the reasons why conspiracy theories spring up with such regularity is due to our desire to impose structure on the world an incredible ability to recognize patterns. Indeed, a recent study showed a correlation between an individual’s need for structure and tendency to believe in a conspiracy theory.
Take this sequence for example:
0 0 1 1 0 0 1 0 0 1 0 0 1 1
Can you see a pattern? Quite possibly – and you aren’t alone. A quick twitter poll (replicating a much more rigorous study) suggested that 56% of people agree with you – even though the sequence was generated by me flipping a coin.