Mirror test

The mirror test – sometimes called the mark test, mirror self-recognition test (MSR), red spot technique, or rouge test – is a behavioural technique developed in 1970 by psychologist Gordon Gallup Jr. as an attempt to determine whether an animal possesses the ability of visual self-recognition. The MSR test is the traditional method for attempting to measure self-awareness. However, there has been agreement that animals can be self-aware in ways not measured by the mirror test, such as distinguishing between their own and others' songs and scents. On the other hand, animals that can pass the MSR do not necessarily have self-awareness. The mirror test – sometimes called the mark test, mirror self-recognition test (MSR), red spot technique, or rouge test – is a behavioural technique developed in 1970 by psychologist Gordon Gallup Jr. as an attempt to determine whether an animal possesses the ability of visual self-recognition. The MSR test is the traditional method for attempting to measure self-awareness. However, there has been agreement that animals can be self-aware in ways not measured by the mirror test, such as distinguishing between their own and others' songs and scents. On the other hand, animals that can pass the MSR do not necessarily have self-awareness. In the classic MSR test, an animal is anaesthetised and then marked (e.g., painted, or a sticker attached) on an area of the body the animal cannot normally see. When the animal recovers from the anesthetic, it is given access to a mirror. If the animal then touches or investigates the mark, it is taken as an indication that the animal perceives the reflected image as itself, rather than of another animal. Very few species have passed the MSR test. As of 2015, only great apes (including humans), a single Asiatic elephant, dolphins, orcas, and the Eurasian magpie have passed the MSR test. A wide range of species have been reported to fail the test, including several species of monkey, giant pandas, sea lions, and dogs. The inspiration for the mirror test comes from an anecdote about Charles Darwin and a captive orangutan. While visiting the London Zoo in 1838, Darwin observed an orangutan, named Jenny, throwing a tantrum after being teased with an apple by her keeper. This started him thinking about the subjective experience of an orangutan. He also watched Jenny gaze into a mirror and noted the possibility that she recognised herself in the reflection. In 1970, Gordon Gallup, Jr., experimentally investigated the possibility of self-recognition with two male and two female wild pre-adolescent chimpanzees (Pan troglodytes), none of which had presumably seen a mirror previously. Each chimpanzee was put into a room by itself for two days. Next, a full-length mirror was placed in the room for a total of 80 hours at periodically decreasing distances. A multitude of behaviours was recorded upon introducing the mirrors to the chimpanzees. Initially, the chimpanzees made threatening gestures at their own images, ostensibly seeing their own reflections as threatening. Eventually, the chimps used their own reflections for self-directed responding behaviours, such as grooming parts of their body previously not observed without a mirror, picking their noses, making faces, and blowing bubbles at their own reflections. Gallup expanded the study by manipulating the chimpanzees' appearance and observing their reaction to their reflection in the mirror. Gallup anaesthetised the chimpanzees and then painted a red alcohol-soluble dye on the eyebrow ridge and on the top half of the opposite ear. When the dye dried, it had virtually no olfactory or tactile cues. Gallup then returned the chimpanzees to the cage (with the mirror removed) and allowed them to regain full consciousness. He then recorded the frequency with which the chimpanzees spontaneously touched the marked areas of skin. After 30 minutes, the mirror was re-introduced into the room and the frequency of touching the marked areas again determined. The frequency of touching increased to 4–10 with the mirror present, compared to only 1 when the mirror had been removed. The chimpanzees sometimes inspected their fingers visually or olfactorily after touching the marks. Other mark-directed behaviour includes turning and adjusting of the body to better view the mark in the mirror, or tactile examination of the mark with an appendage while viewing the mirror. An important aspect of the classical mark-test (or rouge test) is that the mark/dye is non-tactile, preventing attention being drawn to the marking through additional perceptual cues (somesthesis). For this reason, animals in the majority of classical tests are anesthetised. Some tests use a tactile marker. If the creature stares unusually long at the part of its body with the mark or tries to rub it off, then it is said to pass the test. Animals that are considered to be able to recognise themselves in a mirror typically progress through four stages of behaviour when facing a mirror: Gallup conducted a follow-up study in which two chimpanzees with no prior experience of a mirror were put under anesthesia, marked and observed. After recovery, they made no mark-directed behaviours either before or after being provided with a mirror.