pareidolia
Pareidolia is a type of illusion or misperception involving a vague or obscure stimulus being perceived as something clear and distinct. For example, in the discolorations of a burnt tortilla one sees the face of Jesus Christ. Or one sees the image of Mother Theresa or Ronald Reagan in a cinnamon bun or the face of a man in the moon.
Under ordinary circumstances, pareidolia provides a psychological explanation for many delusions based upon sense perception. For example, it explains many UFO sightings, as well as the hearing of sinister messages on records played backwards. Pareidolia explains Elvis, Bigfoot, and Loch Ness Monster sightings. It explains numerous religious apparitions and visions. And it explains why some people see a face or a building in a photograph of the Cydonia region of Mars.
Under clinical circumstances, some psychologists encourage pareidolia as a means to understanding a patient. The most infamous example of this type of clinical procedure is the Rorschach ink blot test.