Tin foil hat

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Man in a tin foil hat Manwithtinfoilhat.jpg
Man in a tin foil hat

A tin foil hat is a hat made from one or more sheets of aluminium foil (commonly called "tin foil" in the United States, New Zealand, Canada, and Ireland), or a piece of conventional headgear lined with foil, often worn in the belief or hope that it shields the brain from threats such as electromagnetic fields, mind control, and mind reading. The notion of wearing homemade headgear for such protection has become a popular stereotype and byword for paranoia, persecutory delusions, and belief in pseudoscience and conspiracy theories.


"Tin foil" is a common misnomer for aluminium foil; packaging metal foil was formerly made out of tin before it was replaced with aluminium. [1]


Some people – "Tin Foil Hatters" – have a belief that such hats prevent mind control by governments, spies, mobsters, corporations, or paranormal beings that employ ESP or the microwave auditory effect. People in many countries who believe they are "targeted individuals", subject to government, corporate, or criminal spying or harassment, have developed websites, conference calls, and support meetings to discuss their concerns, including the idea of protective headgear. [2] Vice Magazine wrote that the tin foil hat in popular culture "can be traced back in a very weird and prescient short story written in 1927 by Julian Huxley" [3] titled "The Tissue-Culture King", wherein the main character uses a metal hat to prevent being mind controlled by the villain scientist. [4] [5] Over time the term "tin foil hat" has become associated with paranoia and conspiracy theories. [6]

Scientific basis

Effects of strong electromagnetic radiation on health have been documented for quite some time. [7] [8] The efficiency of a metal enclosure in blocking electromagnetic radiation depends on the thickness of the foil, as dictated by the "skin depth" of the conductor for a particular wave frequency range of the radiation. For half-millimetre-thick aluminum foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although aluminum foil is not sold in this thickness, so numerous layers of foil would be required to achieve this effect. [9]

In 1962, Allan H. Frey discovered that the microwave auditory effect (i.e., the reception of the induced sounds by radio-frequency electromagnetic signals heard as clicks and buzzes) can be blocked by a patch of wire mesh (rather than foil) placed above the temporal lobe. [10] [11]

In 2005, a tongue-in-cheek experimental study [12] [13] by a group of MIT students found that tin foil hats do shield their wearers from radio waves over most of the tested spectrum, but amplified certain frequencies, around 2.6 GHz and 1.2 GHz.

In 2005, Bruce Perens reported on an encounter between Richard Stallman and security personnel at the UN World Summit on the Information Society, titled "Stallman Gets in Trouble with UN Security for Wearing a Tin-Foil Hat". [14] The tin-foil hat in the title was figurative, as Stallman did not actually devise a tin-foil hat, but instead wrapped an identification card containing a radio-frequency identification device in tin foil in protest against the intrusion on his privacy.

In a 2016 article, the musician and researcher Daniel Wilson writing in paranormal magazine Fortean Times noted an early allusion to an "insulative electrical contrivance encircling the head during thought" in the unusual 1909 non-fiction publication Atomic Consciousness [15] by self-proclaimed "seer" John Palfrey (aka "James Bathurst") who believed such headgear was not effective for his "retention of thoughts and ideas" against a supposed "telepathic impactive impingement". [16]

Tin foil hats have appeared in such films as Signs (2002), [17] Noroi: The Curse (2005), [18] and Futurama: Into the Wild Green Yonder (2009). [19]

The 2019 HBO television series Watchmen features the character Wade Tillman/Looking Glass, a police officer who wears a mask made of reflective foil, and while off-duty, a cap lined in foil to protect his mind from alien psychic attacks. [20]

See also

Related Research Articles

<span class="mw-page-title-main">Electromagnetic radiation</span> Waves of the electromagnetic field

In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. Types of EMR include radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays, all of which are part of the electromagnetic spectrum.

<span class="mw-page-title-main">Electromagnetic spectrum</span> Entire range of frequencies of electromagnetic radiation

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.

<span class="mw-page-title-main">Microwave</span> Electromagnetic radiation with wavelengths from 1 m to 1 mm

Microwave is a form of electromagnetic radiation with wavelengths ranging from about 30 centimeters to one millimeter corresponding to frequencies between 1000 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes UHF, SHF and EHF bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.

Particle radiation is the radiation of energy by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam.

<span class="mw-page-title-main">Radiation</span> Waves or particles moving through space

In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:

<span class="mw-page-title-main">Electromagnetic radiation and health</span> Aspect of public health

Electromagnetic radiation can be classified into two types: ionizing radiation and non-ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize atoms or break chemical bonds. Extreme ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing, and these pose their own special hazards: see radiation poisoning.

The microwave auditory effect, also known as the microwave hearing effect or the Frey effect, consists of the human perception of audible clicks, buzzing, hissing or knocking induced by pulsed or modulated radio frequencies. The perceived sounds are generated directly inside the human head without the need of any receiving electronic device. The effect was first reported by persons working in the vicinity of radar transponders during World War II. In 1961, the American neuroscientist Allan H. Frey studied this phenomenon and was the first to publish information on the nature of the microwave auditory effect. The cause is thought to be thermoelastic expansion of portions of the auditory apparatus, although competing theories explain the results of holographic interferometry tests differently.

<span class="mw-page-title-main">Microwave oven</span> Kitchen cooking appliance

A microwave oven or simply microwave is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm(1–1.5 inches) of a homogeneous, high-water-content food item.

<span class="mw-page-title-main">Radio wave</span> Type of electromagnetic radiation

Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1mm, which is shorter than the diameter of a grain of rice. At 30 Hz the corresponding wavelength is ~10,000 kilometers, which is longer than the radius of the Earth. Wavelength of a radio wave is inversely proportional to its frequency, because its velocity is constant. Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth's atmosphere at a slightly slower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects.

<span class="mw-page-title-main">Faraday cage</span> Enclosure of conductive mesh used to block electric fields

A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive material, or in the case of a Faraday cage, by a mesh of such materials. Faraday cages are named after scientist Michael Faraday, who invented them in 1836.

<span class="mw-page-title-main">Aluminium foil</span> A thin, flexible sheet of aluminium, used for wrapping food and other purposes

Aluminium foil is aluminium prepared in thin metal leaves. The foil is pliable, and can be readily bent or wrapped around objects. Thin foils are fragile and are sometimes laminated with other materials such as plastics or paper to make them stronger and more useful.

Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field. It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).

<span class="mw-page-title-main">Wireless device radiation and health</span>

The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation ; the parts of the head or body nearest to the antenna can absorb this energy and convert it to heat. Since at least the 1990s, scientists have researched whether the now-ubiquitous radiation associated with mobile phone antennas or cell phone towers is affecting human health. Mobile phone networks use various bands of RF radiation, some of which overlap with the microwave range. Other digital wireless systems, such as data communication networks, produce similar radiation.

<span class="mw-page-title-main">Electromagnetic shielding</span> Using conductive or magnetic materials to reduce electromagnetic field intensity

In electrical engineering, electromagnetic shielding is the practice of reducing or blocking the electromagnetic field (EMF) in a space with barriers made of conductive or magnetic materials. It is typically applied to enclosures, for isolating electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. Electromagnetic shielding that blocks radio frequency (RF) electromagnetic radiation is also known as RF shielding.

<span class="mw-page-title-main">Dielectric heating</span> Heating using radio waves

Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material. At higher frequencies, this heating is caused by molecular dipole rotation within the dielectric.

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<span class="mw-page-title-main">Susceptor</span>

A susceptor is a material used for its ability to absorb electromagnetic energy and convert it to heat. The electromagnetic energy is typically radiofrequency or microwave radiation used in industrial heating processes, and also in microwave cooking.

Electronic harassment, electromagnetic torture, or psychotronic torture is a conspiracy theory that malicious actors make use of electromagnetic radiation, radar, and surveillance techniques to transmit sounds and thoughts into people's heads, affect people's bodies, and harass people. Individuals who claim to experience this call themselves "targeted individuals" (TIs). Some claim they are victims of gang stalking and many have created or joined support and advocacy groups.

Microwave burns are burn injuries caused by thermal effects of microwave radiation absorbed in a living organism.

<span class="mw-page-title-main">Non-ionizing radiation</span> Harmless low-frequency radiation

Non-ionizingradiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. Instead of producing charged ions when passing through matter, non-ionizing electromagnetic radiation has sufficient energy only for excitation. Non-ionizing radiation is not a significant health risk. In contrast, ionizing radiation has a higher frequency and shorter wavelength than non-ionizing radiation, and can be a serious health hazard: exposure to it can cause burns, radiation sickness, many kinds of cancer, and genetic damage. Using ionizing radiation requires elaborate radiological protection measures, which in general are not required with non-ionizing radiation.


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  5. Huxley, Julian (August 1927). "The Tissue-Culture King". Amazing Stories . 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.
  6. "Hey Crazy – Get a New Hat". Bostonist. 15 November 2005. Archived from the original on 3 May 2007. Retrieved 5 April 2007.
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  14. "Friday, November 18: Richard Stallman Gets in Trouble with UN Security for Wearing a Tin-Foil Hat". 18 November 2005. Archived from the original on 27 April 2006.
  15. Bathurst, James (1909). Atomic Consciousness Abridgement. W. Manning, London.
  16. Wilson, Daniel (June 2016). "Atomic-Consciousness". Fortean Times .
  17. Lang, Cady (20 September 2019). "Area 51 Raid But Make It Fashion: It Takes a Lot to Stand Out at Alien-Themed Festival But This Guy's Tin Foil Hat Is Working". Time . Retrieved 10 March 2020.
  18. Whittaker, Richard (9 July 2017). "DVDanger: Don't Knock Twice". The Austin Chronicle . Retrieved 14 April 2020.
  19. Miller III, Randy (1 February 2009). "Futurama: Into The Wild Green Yonder". DVD Talk . Retrieved 10 March 2020.
  20. Erdmann, Kevin (18 November 2019). "Watchmen: Biggest Comic Easter Eggs in Episode 5". Screen Rant . Retrieved 10 March 2020.