Why pareidolia happens
There are a number of theories as to the cause of this phenomenon. Experts say pareidolia provides a psychological determination for many delusions that involve the senses. They believe pareidolia could be behind numerous sightings of UFOs, Elvis and the Loch Ness Monster and the hearing of disturbing messages on records when they are played backwards.
Pareidolia often has religious overtones. A study in Finland found that people who are religious or believe strongly in the supernatural are more likely to see faces in lifeless objects and landscapes.
Carl Sagan, the American cosmologist and author, made the case that pareidolia was a survival tool. In his 1995 book, "The Demon-Haunted World – Science as a Candle in the Dark," he argued that this ability to recognize faces from a distance or in poor visibility was an important survival technique. While this instinct enables humans to instantly judge whether an oncoming person is a friend or foe, Sagan noted that it could result in some misinterpretation of random images or patterns of light and shade as being faces.
Leonardo da Vinci wrote about pareidolia as an artistic device. "If you look at any walls spotted with various stains or with a mixture of different kinds of stones, if you are about to invent some scene you will be able to see in it a resemblance to various different landscapes adorned with mountains, rivers, rocks, trees, plains, wide valleys, and various groups of hills," he wrote in a passage in one of his extensive notebooks.
Sometimes artists use this phenomenon to their advantage by embedding hidden images in their work. Observers often view other objects in Georgia O'Keeffe's flower paintings, for example.
In 1971, the Latvian writer and intellectual Konstantīns Raudive detailed what he believed was the discovery of electronic voice phenomenon (EVP). EVP has been described as "auditory pareidolia." The allegations of hidden messages in popular music have also been described as auditory pareidolia.
The Rorschach inkblot test uses pareidolia in an attempt to gain insight into a person's mental state. Since the cards have been designed without any specific image in mind, this is an example of "directed pareidolia."
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