Tin foil hat

A person wearing a tin foil hat.

A tin foil hat (TFH) is a piece of headgear made from one or more sheets of aluminium foil or similar material. Alternatively it may be a conventional hat lined with foil. Some people wear the hats in the belief that they act to shield the brain from such influences as electromagnetic fields, or against mind control and/or mind reading.

The concept of wearing a tin foil hat for protection from such threats has become a popular stereotype and term of derision; the phrase serves as a byword for paranoia and is associated with conspiracy theorists. In Japan, there is a religious cult, Pana Wave, based entirely on the conspiracy theory of electromagnetic field. They dress in white clothes and wear specially made tin foil hats.[1][2]

Tin foil hats and paranoia

The reasons for their use include the supposed prevention of perceived harassment from governments, spies or paranormal beings. These draw on the stereotypical images of mind control operating by ESP or technological means, like microwave radiation. Belief in the effectiveness of tin foil hats is popularly associated with paranoia or mental illness.

Scientific basis

The notion that a tin foil hat can significantly reduce the intensity of incident RF radiation on the wearer's brain is not completely without a basis in scientific fact. A well constructed tin foil enclosure would approximate a Faraday cage, reducing the amount of (notionally harmless) radiofrequency electromagnetic radiation inside. A common high school physics demonstration involves placing an AM radio on tin foil, and then covering the radio with a metal bucket. This leads to a noticeable reduction in signal strength. The efficiency of such an enclosure in blocking such radiation depends on the thickness of the tin foil, as dictated by the skin depth, the distance the radiation can propagate in a particular non-ideal conductor. For half-millimeter-thick tin foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked.

The effectiveness of the tin foil hat as electromagnetic shielding for stopping radio waves is greatly reduced by the fact that it is not a complete enclosure. Placing an AM radio under a metal bucket without a conductive layer underneath demonstrates the relative ineffectiveness of such a setup. Indeed, because the effect of an ungrounded Faraday cage is to partially reflect the incident radiation, a radio wave that is incident on the inner surface of the hat (i.e., coming from underneath the hat-wearer) would be reflected and partially 'focused' towards the user's brain. While tin foil hats may have originated in some understanding of the Faraday cage effect, the use of such a hat to attenuate radio waves belongs properly to the realm of pseudoscience.

A study by graduate students at MIT determined that a tin foil hat could either amplify or attenuate incoming radiation depending on frequency; the effect was observed to be roughly independent of the relative placement of the wearer and radiation source. At GHz wavelengths, the skin depth is less than the thickness of even the thinnest foil.

Tin foil hats are seen by some as a protective measure against the effects of electromagnetic radiation (EMR). Despite some allegations that EMR exposure has negative health consequences, at this time, no link has been verifiably proven between the radio-frequency EMR that tin foil hats are meant to protect against and subsequent ill health.

References in popular culture

Tin foil hats were worn in the movie Signs to protect from alien mind-reading tactics, and coincidentally were alluded to in another Mel Gibson movie, Conspiracy Theory.

Tin foil hats are frequently used in popular culture to indicate paranoia, especially as induced by mental illness.

Eastenders character Joe Wicks was briefly portrayed constructing and wearing his own tin foil hat as part of a storyline which saw him suffering from schizophrenia.

In an episode of the Discovery Channel television show Mythbusters dealing with microwave oven myths, Adam Savage constructed a tin foil hat to wear while working in the shop, as Jamie Hyneman had taken apart a microwave in an attempt to design a "microwave gun." That hat was not intended to provide serious protection for Adam, and was a tongue-in-cheek reference to their use. However, Adam was seriously concerned for the safety of the show's cast and crew while working with an uncovered microwave.

In late 2004, the MMORPG Anarchy Online introduced an in-game item called 'Tinfoil Hat' as part of the game expansion Alien Invasion. The item is rare, but according to an online Anarchy Online item database, it offers some small bonuses. It is, however, an item made purely for its entertainment value, with humorous descriptions of how it can 'block out alien mind control' and that it looks 'very good with an accompanying white coat which had extremely long sleeves'. The in-game item looks like silver tract-shaped headgear.

In April 2007, MMORPG World of Warcraft announced a new in-game item on its website named the 'Tinfoil Hat'. The hat came complete with tongue-in-cheek statistics such as hiding the player's profile from The Armory (an online character database), and allowing the player to see 'the truth'. The item was later revealed to be an April Fool's Day joke.

In the final Futurama film, Futurama: Into the Wild Green Yonder Fry wears a tin foil hat to stop being able to hear other peoples thoughts.

See also

• List of hats and headgear

External links

• Do tinfoil helmets provide adequate protection against mind control rays? – from The Straight Dope
• Aluminium Foil Deflector Beanie – parody
• "EMF Safety Garments" including "Shielded Cap"
• Tinfoil Hat Mind Control Musical Animation – parody
• Tinfoil hats attract mind-control signals, boffins learn
• Tin foil hats (with detailed instructions) to prevent alien abductions - Possibly a parody, fun read either way. Includes alleged user testimonials.