Friday, October 1, 2010

The Pseudoscience of Ghost Hunting part 1: EVP

Electronic Voice Phenomena. Recorded voices of the discarnate,
discovered on playback of audio recording devices. A common practice of amateur ghost hunters using cassette recorders or dictaphones. Typically during an investigation, a series of questions are asked with a moment of silence between them. Afterward, the audio is poured over and scrutinized, listening for answers from the deceased and more often than not, they are successful.
Spend two minutes on google and you'll find dozens of examples of this. Here are a few selections:

Can you hear them? They're a little hard to make out, but listen again. The first one says, "Shit happens." and the second says "I'm Bob."
Now, that's all dependent on the interpretation of the person reviewing the audio.

The EVP phenomena first emerged in 1959 when Swedish opera singer
Friedrich Jurgenson noticed a strange sound on one of his recordings of bird songs. It was a voice allegedly saying something along the lines of "Bird songs at night". Jurgenson assumed it was little more than radio or CB interference until he discovered the voices reoccurred and seemed to be speaking directly to him. After a long series of these recordings, Jurgenson was compelled to write books of these anomallies, Rosterna fran Rymden (“Voices from space”) and later, Sprechfunk mit Verstorbenen (“Radio-link with the dead”).

In 1964, Latvian psychologist Dr Konstantin Raudive read Rosterna fran Rymden and arranged to meet Jurgenson. In '65 they conducted a series of recordings and interprited one of such to have recorded a number of voices speaking in German, French, and Latvian including the phrase “Va dormir, Margarete” ("Go to sleep, Margaret”).
Raudive later wrote : “These words made a deep impression on me, as Margarete Petrautzki had died recently, and her illness and death had greatly affected me.” After he spent the last years of his life exploring this phenomina, recording over 100,000 audio recordings. This culminated in the 1971 publication of his book Breakthrough

Raudive developed several different approaches to recording EVP, and he referred to:

  1. Microphone voices: one simply leaves the tape recorder running, with no one talking; he indicated that one can even disconnect the microphone.
  2. Radio voices: one records the white noise from a radio that is not tuned to any station.
  3. Diode voices: one records from what is essentially a crystal set not tuned to a station.

Raudive delineated a number of characteristics of the voices, (as laid out in Breakthrough):

  1. “The voice entities speak very rapidly, in a mixture of languages, sometimes as many as five or six in one sentence.”
  2. “They speak in a definite rhythm, which seems forced on them.”
  3. “The rhythmic mode imposes a shortened, telegram-style phrase or sentence.”
  4. Probably because of this, “grammatical rules are frequently abandoned and neologisms abound.”
Today, nearly every paranormal investigator, including the groups featured on cable tv, practice in the recording of EVPs and there are roughly 50,000 websites dedicated to the recordings.

Here are some more examples:

Pretty compelling, right? Seems like more than just misinterpretations of white noise (excluding the hoaxes). How can anyone claim that it is anything but definite speech?

Now listen to "this" .

Sine-wave speech is a form of artificially degraded speech first developed by Robert Remez and Philip Rubin at Haskins Laboratory.

In this work, Remez and colleagues demonstrated a dramatic change in the way in which sine-wave speech sentences are perceived, depending on listener's specific prior knowledge.

Most naive listeners hear this as a set of simultaneous whistles, or science fiction sounds. However, for listeners that have previously heard this "sound" . Now listen to the first again.

Listening to the sine-wave speech sound again produces a very different perception of a fully intelligible spoken sentence. This dramatic change in perception is an example of "perceptual insight" or pop-out. We have argued that this form of pop-out is an example of a top-down perceptual process produced by higher-level knowledge and expectations concerning sounds that can potentially be heard as speech

Here is another example:

"sinewave 1" "clear speech 1"

The problem is that anyone recording these "voices" (in the case of ghost hunting) is already looking for them. They have a prior bias and are going to over- examine any anomalous sound and claim they hear speech. I believe that in most cases, the real culprit behind hearing voices of the dead in your tape recordings is Paradoilia. Yes, the same reason you see Jesus in your cheetos. After all, how is the spirit of a deceased person able to produce sound without vocal chords? The human brain is a very powerful tool, able to proccess random information into recognizable images and sounds. This is how we developed language and writing. Don't sell yourself short by writing these sounds off as something paranormal.

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