The participant just has to gaze at his or her reflected face within the mirror and usually “after less than a minute, the observer began to perceive the strange-face illusion”. The author, Italian psychologist Giovanni Caputo, describes his set up which seems to reliably trigger the illusion: you need a room lit only by a dim lamp (he suggests a 25W bulb) that is placed behind the sitter, while the participant stares into a large mirror placed about 40 cm in front.
To trigger the illusion you need to stare at your own reflection in a dimly lit room.
An intriguing article has just been published in the journal Perception about a never-before-described visual illusion where your own reflection in the mirror seems to become distorted and shifts identity.
