Mirror test

The mirror test—sometimes called the mark test, mirror self-recognition (MSR) test, red spot technique, or rouge test—is a behavioral technique developed in 1970 by American psychologist Gordon Gallup Jr. to determine whether an animal possesses the ability of visual self-recognition.^[1] In this test, an animal is anesthetized and then marked (e.g. paint or sticker) on an area of the body the animal normally cannot see (e.g. forehead). When the animal recovers from the anesthetic, it is given access to a mirror. If the animal then touches or investigates the mark on itself, it is taken as an indication that the animal perceives the reflected image as an image of itself, rather than of another animal.

The MSR test became the traditional method for measuring physiological and cognitive self-awareness. Very few species passed it. However, several critiques have emerged that call into question the value of Gallup's test.^[2][3] Studies have challenged Gallup's results^[2]; others have found that animals can be self-aware in ways not measured by the test, such as distinguishing between their own and others' songs and scents.^[4]