CBS The Case of: JonBenét Ramsey ep 1 and Electronic voice phenomenon

Within ghost hunting and parapsychology, electronic voice phenomena (EVP) are sounds found on electronic recordings that are interpreted as spirit voices that have been either unintentionally recorded or intentionally requested and recorded. Parapsychologist Konstantīns Raudive, who popularized the idea in the 1970s, described EVP as typically brief, usually the length of a word or short phrase.[1]

Enthusiasts consider EVP to be a form of paranormal phenomena often found in recordings with static or other background noise. However, psychologists regard EVP as a form of auditory pareidolia (interpreting random sounds as voices in one's own language) and a pseudoscience promulgated by popular culture. Rational explanations for EVP include apophenia (perceiving patterns in random information), equipment artifacts, and hoaxes.[2][3]

Explanations and origins

Paranormal claims for the origin of EVP include living humans imprinting thoughts directly on an electronic medium through psychokinesis[29] and communication by discarnate entities such as spirits,[30][31] nature energies, beings from other dimensions, or extraterrestrials.[32] Paranormal explanations for EVP generally assume production of EVP by a communicating intelligence through means other than the typical functioning of communication technologies. Natural explanations for reported instances of EVP tend to dispute this assumption explicitly and provide explanations which do not require novel mechanisms that are not based on recognized scientific phenomena.

One study, by psychologist Imants Barušs, was unable to replicate suggested paranormal origins for EVP recorded under controlled conditions.[33] Brian Regal in Pseudoscience: A Critical Encyclopedia (2009) has written "A case can be made for the idea that many EVPs are artifacts of the recording process itself with which the operators are unfamiliar. The majority of EVPS have alternative, nonspiritual sources; anomalous ones have no clear proof they are of spiritual origin."[34]
Natural explanations

There are a number of simple scientific explanations that can account for why some listeners to the static on audio devices may believe they hear voices, including radio interference and the tendency of the human brain to recognize patterns in random stimuli.[35] Some recordings may be hoaxes created by frauds or pranksters.[35]
Psychology and perception

Auditory pareidolia is a situation created when the brain incorrectly interprets random patterns as being familiar patterns.[36] In the case of EVP it could result in an observer interpreting random noise on an audio recording as being the familiar sound of a human voice.[35][37][38] The propensity for an apparent voice heard in white noise recordings to be in a language understood well by those researching it, rather than in an unfamiliar language, has been cited as evidence of this,[35] and a broad class of phenomena referred to by author Joe Banks as Rorschach Audio has been described as a global explanation for all manifestations of EVP.[39][40][41][42]

Skeptics such as David Federlein, Chris French, Terence Hines and Michael Shermer say that EVP are usually recorded by raising the "noise floor" – the electrical noise created by all electrical devices – in order to create white noise. When this noise is filtered, it can be made to produce noises which sound like speech. Federlein says that this is no different from using a wah pedal on a guitar, which is a focused sweep filter which moves around the spectrum and creates open vowel sounds. This, according to Federlein, sounds exactly like some EVP. This, in combination with such things as cross modulation of radio stations or faulty ground loops can cause the impression of paranormal voices.[4] The human brain evolved to recognize patterns, and if a person listens to enough noise the brain will detect words, even when there is no intelligent source for them.[43][44] Expectation also plays an important part in making people believe they are hearing voices in random noise.[45]

Apophenia is related to, but distinct from pareidolia.[46] Apophenia is defined as "the spontaneous finding of connections or meaning in things which are random, unconnected or meaningless", and has been put forward as a possible explanation.[47] According to the psychologist James Alcock what people hear in EVP recordings can best be explained by apophenia, cross-modulation or expectation and wishful thinking. Alcock concluded "Electronic Voice Phenomena are the products of hope and expectation; the claims wither away under the light of scientific scrutiny."[48]
Physics

Interference, for example, is seen in certain EVP recordings, especially those recorded on devices which contain RLC circuitry. These cases represent radio signals of voices or other sounds from broadcast sources.[49] Interference from CB Radio transmissions and wireless baby monitors, or anomalies generated through cross modulation from other electronic devices, are all documented phenomena.[35] It is even possible for circuits to resonate without any internal power source by means of radio reception.[49]

Capture errors are anomalies created by the method used to capture audio signals, such as noise generated through the over-amplification of a signal at the point of recording.[35][50]

Artifacts created during attempts to boost the clarity of an existing recording might explain some EVP. Methods include re-sampling, frequency isolation, and noise reduction or enhancement, which can cause recordings to take on qualities significantly different from those that were present in the original recording.[35][51]

The very first EVP recordings may have originated from the use of tape recording equipment with poorly aligned erasure and recording heads, resulting in the incomplete erasure of previous audio recordings on the tape. This could allow a small percentage of previous content to be superimposed or mixed into a new 'silent' recording.[52][citation needed]
Sporadic meteors and meteor showers

For all radio transmissions above 30 MHz (which are not reflected by the ionosphere) there is a possibility of meteor reflection of the radio signal.[53] Meteors leave a trail of ionised particles and electrons as they pass through the upper atmosphere (a process called ablation) which reflect transmission radio waves which would usually flow into space.[54] These reflected waves are from transmitters which are below the horizon of the received meteor reflection. In Europe this means the brief scattered wave may carry a foreign voice which can interfere with radio receivers. Meteor reflected radio waves last between 0.05 seconds and 1 second, depending on the size of the meteor.[55]

Auditory pareidolia is a situation created when the brain incorrectly interprets random patterns as being familiar patterns.[36] In the case of EVP it could result in an observer interpreting random noise on an audio recording as being the familiar sound of a human voice.[35][37][38] The propensity for an apparent voice heard in white noise recordings to be in a language understood well by those researching it, rather than in an unfamiliar language, has been cited as evidence of this,[35] and a broad class of phenomena referred to by author Joe Banks as Rorschach Audio has been described as a global explanation for all manifestations of EVP.[39][40][41][42]

Skeptics such as David Federlein, Chris French, Terence Hines and Michael Shermer say that EVP are usually recorded by raising the "noise floor" – the electrical noise created by all electrical devices – in order to create white noise. When this noise is filtered, it can be made to produce noises which sound like speech.