The term pareidolia describes a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant. Common examples include seeing images of animals or faces in clouds, the man in the moon, and hearing hidden messages on records played in reverse. The word comes from the Greek para- —"beside", "with" or "alongside"- meaning, in this context, something faulty or wrong (as in paraphasia, disordered speech)—and eidolon—"image" (the diminutive of eidos—"image", "form", "shape"). Pareidolia is a type of apophenia.
In 1978, a New Mexican woman found that the burn marks on a tortilla she had made appeared similar to the traditional western depiction of Jesus Christ's face. Thousands of people came to see the framed tortilla.
The recent publicity surrounding sightings of religious figures and other surprising images in ordinary objects, combined with the growing popularity of online auctions, has spawned a market for such items on eBay. One famous instance was a grilled cheese sandwich with the Virgin Mary's face.
In September, 2007, the so-called "monkey tree phenomenon" caused a minor social mania in Singapore. A callus on a tree there resembles a monkey, and believers have flocked to the tree to pay homage to the Monkey God.
From the late 1970's through the early 1980's, Japanese researcher Chonosuke Okamura self-published a famous series of reports titled "Original Report of the Okamura Fossil Laboratory" in which he described tiny inclusions in polished limestone from the Silurian period (425 mya) as being preserved fossil remains of tiny humans, gorillas, dogs, dragons, dinosaurs, and other organisms, all of them only millimeters long, leading him to claim "There have been no changes in the bodies of mankind since the Silurian period . . . except for a growth in stature from 3.5 mm to 1,700 mm.
The allegations of backmasking in popular music have also been described as pareidolia.