The tin foil hat (misnomer for aluminum foil, which is the product actually sold in stores) is a pervasive metaphor for paranoia and conspiracy theorists, but there’s no record of any real life conspiracy theorist ever seriously fashioning some Reynold’s wrap into headwear. How, then, did this bit of absurd fashion come to be associated with paranoia and mind control prevention?

Everyone knew what was being referenced in the above still from the 2003 film Signs because the notion of tin foil hats has been cliche for a while. It’s more of a symbol, a metaphor people use to swiftly discredit the validity of an argument or idea, to quickly label it is an unfounded conspiracy theory. When people literally wear tinfoil hats in real life, they usually do so with irony.

There is some science behind the idea of wearing a metal hat for protection, but a hat contracted of the everyday foil we use to wrap up sandwiches and reheat pizza is a faulty protector. The basic argument for potential security offered by a metal hat is the Faraday cage: a metal enclosure that can protect the interior against electrostatic charges and electromagnetic waves. Microwaves, elevators, and scan rooms for MRI machines are all Faraday cages. Shoplifters often use foil-lined bags to work as makeshift Faraday cages to prevent security tags inside from being set off by detectors. A hat, however, can’t ever really be a Faraday cage because it isn’t an enclosure.

In 2005 some MIT students experimented with tin foil hats and found that while they were successful in blocking radio waves, these iconic hats actually amplify other waves, including waves used by mobile devices, satellites, and aeronautical radio navigation. In other words, if the government (or aliens) is surveilling your communications, wearing a tin foil hat has the potential to make it easier for them to do so.

The idea of wearing hats made of metallic foil in order to block mind control is often cited as having first originated in a 1927 short story by Julian Huxley, Aldous Huxley’s brother. Called “The Tissue-Culture King,” the story is about two Englishmen who become captured by a king in Africa. It’s a sci-fi tale that follows the men as they win the King’s good favor by culturing his tissue to make him immortal and develop mind control techniques to help him control his people. They then devise a plan to escape back to England, and protect themselves from their own mind control technology by wearing caps made of tin foil.

“The reader will perhaps ask how we ourselves expected to escape from the clutches of the super-consciousness we had created. Well, we had discovered that metal was relatively impervious to the telepathic effect, and had prepared for ourselves a sort of tin pulpit, behind which we could stand while conducting experiments. This, combined with caps of metal foil, enormously reduced the effects on ourselves. We had not informed Bugala of this property of metal.”

The tin foil hat is a costume, a reminder of how silly it can be to trust our own minds. It’s often used to mock others and what they’ll fall for, but its important to remember that we are all just trying to make sense out of a senseless world, and it gives us comfort to think we have some sort of stronghold on a secret truth invisible to everyone else.

The image used for a popular tin foil hat meme