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The mirror test—sometimes called the mark test, mirror self-recognition (MSR) test, red spot technique, or rouge test—is a
behavioral Behavior (American English) or behaviour (British English) is the range of actions of individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate p ...
technique developed in 1970 by American psychologist Gordon Gallup Jr. to determine whether an animal possesses the ability of visual self-recognition. 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 A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...
. 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 In philosophy of self, philosophy, self-awareness is the awareness and reflection of one's own personality or individuality, including traits, feelings, and behaviors. It is not to be confused with consciousness in the sense of qualia. While ...
. Very few species passed it. However, several critiques have emerged that call into question the value of Gallup's test.Swartz, Karyl; Evans, Sian. "Anthropomorphism, Anecdotes, and Mirrors" in Mitchell, Robert; Thompson, Nicholas; and Miles, Lyn ''Anthropomorphism, Anecdotes, and Animals.'' New York: State University of New York Press (1997). pp 296-310. Studies have challenged Gallup's results; 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 A song is a musical composition performed by the human voice. The voice often carries the melody (a series of distinct and fixed pitches) using patterns of sound and silence. Songs have a structure, such as the common ABA form, and are usuall ...
and scents.


Method and history

The inspiration for the mirror test comes from an
anecdote An anecdote is "a story with a point", such as to communicate an abstract idea about a person, place, or thing through the concrete details of a short narrative or to characterize by delineating a specific quirk or trait. Anecdotes may be real ...
about
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all speci ...
and a captive orangutan. While visiting the
London Zoo London Zoo, previously known as ZSL London Zoo or London Zoological Gardens and sometimes called Regent's Park Zoo, is the world's oldest scientific zoo. It was opened in London on 27 April 1828 and was originally intended to be used as a colle ...
in 1838, Darwin observed an
orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genus ...
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 recognized herself in the reflection.Carl Zimmer. ''The Descent of Man: The Concise Edition.'' excerpt available a
http://carlzimmer.com/books/descentofman/excerpt.html
.
In 1970, Gordon Gallup Jr. experimentally investigated the possibility of self-recognition with two male and two female wild preadolescent
chimpanzee The chimpanzee (; ''Pan troglodytes''), also simply known as the chimp, is a species of Hominidae, great ape native to the forests and savannahs of tropical Africa. It has four confirmed subspecies and a fifth proposed one. When its close rel ...
s (''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 behaviors was recorded upon introducing the mirrors to the chimpanzees. Initially, the chimpanzees made threatening gestures at their images, ostensibly seeing their reflections as threatening. Eventually, the chimps used their reflections for self-directed responding behaviors, such as grooming parts of their body previously not observed without a mirror, picking their noses, making faces, and blowing bubbles at their reflections. Gallup expanded the study by manipulating the chimpanzees' appearance and observing their reaction to their reflection in the mirror. Gallup anesthetized the chimps and then painted a red alcohol-soluble dye on the eyebrow ridge and the top half of the opposite ear. When the dye dried, it had virtually no olfactory or tactile cues. Gallup then removed the mirror before returning the chimpanzees to the cage. After regaining full consciousness, he recorded the frequency with which the chimps spontaneously touched the marked areas of skin. After 30 minutes, the mirror was reintroduced into the cage, and the frequency of touching the marked areas was again determined. With the mirror present, the frequency increased from four to ten, compared to only one when the mirror had been removed. The chimpanzees sometimes visually or olfactorily inspected their fingers after touching the marks. Other mark-directed behavior included turning and adjusting the body to better view the mark in the mirror or tactile examination of the mark with an appendage while viewing the mirror. An essential aspect of the classical mark test (or rouge test) is that the mark/dye is nontactile, preventing attention from being drawn to the marking through additional perceptual cues ( somesthesis). For this reason, animals in the majority of classical tests are anesthetized. 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 recognize themselves in a mirror typically progress through four stages of behavior when facing a mirror: The rouge test was also done by Michael Lewis and Jeanne Brooks-Gunn in 1979 for the purpose of self-recognition with human mothers and their children.


Implication and alternate explanations

The default implication drawn from Gallup's test is that those animals who pass the test possess some form of self-recognition. However, a number of authors have suggested alternative explanations of a pass. For example, Povinelli suggests that the animal may see the reflection as some odd entity that it is able to control through its own movements. When the reflected entity has a mark on it, then the animal can remove the mark or alert the reflected entity to it using its own movements to do so. Critically, this explanation does not assume that the animals necessarily see the reflected entity as "self".


Criticism

The MSR test has been criticized for several reasons, in particular because it may result in false negative findings.


Perception

It may be of limited value when applied to species that primarily use senses other than vision. Humans have been determined by
biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...
s to have some of the best eyesight amongst animals, exceeding the overwhelming majority in daylight settings, though a few species have better. By contrast, dogs for example mainly use smell and
hearing Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory sci ...
; vision is used third. This may be why dogs fail the MSR test. With this in mind, biologist Marc Bekoff developed a scent-based paradigm using dog urine to test self-recognition in canines. He tested his own dog, but his results were inconclusive. Dog cognition researcher Alexandra Horowitz formalized Bekoff's idea in a controlled experiment, first reported in 2016 and published in 2017. She compared the dogs' behavior when examining their own and others' odors, and also when examining their own odor with an added smell "mark" analogous to the visual mark in MSR tests. These subjects not only discriminated their own odor from that of other dogs, as Bekoff had found, but also spent more time investigating their own odor "image" when it was modified, as subjects who pass the MSR test do. A 2016 study suggested an ethological approach, the "Sniff test of self-recognition (STSR)" which did not shed light on different ways of checking for self-recognition. Dogs also show self-awareness in the size and movement of their bodies. Garter snakes, a relatively social snake species, have also passed an odor based "mirror" test.


Social motivation

Another concern with the MSR test is that some species quickly respond aggressively to their mirror reflection as if it were a threatening conspecific, thereby preventing the animal from calmly considering what the reflection actually represents. This may be why monkeys fail the MSR test.


Disinterest

In an MSR test, animals may not recognise the mark as abnormal, or may not be sufficiently motivated to react to it. However, this does not mean they are unable to recognize themselves. For example, in an MSR test conducted on three elephants, only one elephant passed the test, but the two elephants that failed still demonstrated behaviors that can be interpreted as self-recognition. The researchers commented that the elephants might not have touched the mark because it was not important enough to them. Similarly, lesser apes infrequently engage in self-grooming, which may explain their failure to touch a mark on their heads in the mirror test. In response to the question of the subject's motivation to clean, another study modified the test by introducing child subjects to a doll with a rouge spot under its eye and asking the child to help clean the doll. After establishing that the mark was abnormal and to be cleaned, the doll was put away and the test continued. This modification increased the number of self-recognisers.


Ambiguity

Frans de Waal, a biologist and primatologist at Emory University, has stated that self-awareness is not binary, and the mirror test should not be relied upon as a sole indicator of self-awareness, though it is a good test to have. Different animals adapt to the mirror in different ways.


Non-human animals

Several studies using a wide range of species have investigated the occurrence of spontaneous, mark-directed behavior when given a mirror, as originally proposed by Gallup. Most marked animals given a mirror initially respond with social behavior, such as aggressive displays, and continue to do so during repeated testing. Only a few species have touched or directed behavior toward the mark, thereby passing the classic MSR test. Findings in MSR studies are not always conclusive. Even in chimpanzees, the species most studied and with the most convincing findings, clear-cut evidence of self-recognition is not obtained in all individuals tested. Prevalence is about 75% in young adults and considerably less in young and aging individuals. Until the 2008 study on magpies, self-recognition was thought to reside in the
neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, ...
area of the brain. However, this brain region is absent in nonmammals. Self-recognition may be a case of
convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...
, where similar evolutionary pressures result in similar behaviors or traits, although species arrive at them by different routes, and the underlying mechanism may be different.


Animals that have passed


Mammals


= Cetaceans

= *
Bottlenose dolphin The bottlenose dolphin is a toothed whale in the genus ''Tursiops''. They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus contains three species: the common bot ...
(''Tursiops truncatus''): Researchers in a study on two male bottlenose dolphins observed their reactions to mirrors after having a mark placed on them. Reactions such as decreased delay in approaching the mirror, repetitious head circling and close viewing of the eye or genital region that had been marked, were reported as evidence of MSR in these species. * Killer whale (''Orcinus orca''): Killer whales and
false killer whale The false killer whale (''Pseudorca crassidens'') is a species of oceanic dolphin that is the only extant representative of the genus ''Pseudorca''. It is found in oceans worldwide but mainly in tropical regions. It was first species descriptio ...
s (''Pseudorca crassidens'') may be able to recognise themselves in mirrors.


= Primates

= *
Bonobo The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee (less often the dwarf chimpanzee or gracile chimpanzee), is an endangered great ape and one of the two species making up the genus ''Pan (genus), Pan'' (the other bei ...
('' Pan paniscus'') *
Bornean orangutan The Bornean orangutan (''Pongo pygmaeus'') is an orangutan species endemic to the island of Borneo. It belongs to the only genus of great apes native to Asia and is the largest of the three ''Pongo'' species. It has a coarse, reddish coat and up ...
(''
Pongo pygmaeus Pongo may refer to: Places * Pongo (geography), canyon or narrow gorge in the Upper Amazon * Pongo River (disambiguation), several rivers or estuaries in Africa * Pongo, Kentucky, an unincorporated community * Pongo, Longleng, village in Long ...
''): However, mirror tests with an infant (2-year-old), male orangutan failed to reveal self-recognition. *
Chimpanzee The chimpanzee (; ''Pan troglodytes''), also simply known as the chimp, is a species of Hominidae, great ape native to the forests and savannahs of tropical Africa. It has four confirmed subspecies and a fifth proposed one. When its close rel ...
('' Pan troglodytes''): However, mirror tests with an infant (11 months old) male chimpanzee failed to reveal self-recognition. Two young chimpanzees showed retention of MSR after one year without access to mirrors. *
Western gorilla The western gorilla (''Gorilla gorilla'') is a great ape found in Africa, one of two species of the hominid genus ''Gorilla''. Large and robust with males weighing around , the species is found in a region of midwest Africa, geographically iso ...
('' Gorilla gorilla''): Findings for western gorillas have been mixed; more so than for the other great apes. At least four studies have reported that
gorilla Gorillas are primarily herbivorous, terrestrial great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or five su ...
s failed to show self-recognition. However, other studies have shown self-recognition in captive gorillas with extensive
human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
contact. Such gorillas show less aversion to direct eye contact than wild gorillas. In wild gorillas, as in many other animals, prolonged direct eye contact is an aggressive gesture, and gorillas may fail the mirror test because they deliberately avoid closely examining or making eye contact with their reflections. Gorillas who have passed the MSR were habituated to the mirror before testing and were not subject to anesthesia during the marking process. Koko was among the gorillas who passed the MSR test under these circumstances.


= Proboscidea

= *
Asian elephant The Asian elephant (''Elephas maximus''), also known as the Asiatic elephant, is the only living ''Elephas'' species. It is the largest living land animal in Asia and the second largest living Elephantidae, elephantid in the world. It is char ...
(''Elephas maximus''): In a study performed in 2006, three female Asian elephants were exposed to a large mirror to investigate their responses. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the MSR test. One of the elephants showed mark-directed behavior, though the other two did not. An earlier study failed to find MSR in two Asian elephants; it was claimed this was because the mirror was too small.


= Rodents

= *
House mouse The house mouse (''Mus musculus'') is a small mammal of the rodent family Muridae, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus '' Mus''. A ...
(''Mus musculus)''


Birds

*
Eurasian magpie The Eurasian magpie or common magpie (''Pica pica'') is a resident breeding bird throughout the northern part of the Eurasian continent. It is one of several birds in the crow family (corvids) designated magpies, and belongs to the Holarctic r ...
(''Pica pica''): The Eurasian magpie is the first non-mammal to have been found to pass the mirror test. In 2008, researchers applied a small red, yellow, or black sticker to the throat of five Eurasian magpies, where they could be seen by the bird only by using a mirror. The birds were then given a mirror. The feel of the sticker on their throats did not seem to alarm the magpies. However, when the birds with colored stickers glimpsed themselves in the mirror, they scratched at their throats—a clear indication that they recognised the image in the mirror as their own. Those that received a black sticker, invisible against the black neck feathers, did not react. In 2020, researchers attempted to closely replicate the 2008 study with a larger number of magpies, and failed to confirm the results of the 2008 study. The researchers stated that while these results did not disprove the 2008 study, the failure to replicate indicated the results of the original study should be treated with caution. * Indian house crow (''Corvus splendens''): House crows were found to pass the mirror test in 2019. Six wild-caught crows had a red or yellow mark applied to their throat, then given a mirror. Their reactions were then compared to behaviour exhibited when the mark was applied in absence of a mirror, and when a black mark — not visible against the black throat — was applied both with and without a mirror. Four of the six birds displayed mark-directed behaviour spontaneously when first shown a mirror. The behaviours of these birds were then compared; the birds showed statistically increased levels of plumage ruffling and head shaking in the mark-mirror trials. Another study done on five house crows failed to replicate the result, to which they list several experimental differences, such as length of mirror and mark exposure and sticker weight. They additionally note that only two of the four crows that exhibited mark-directed behaviour in the original experiment did so at a high frequency, and that of the other two, one was preening at high levels during mirror exposure without a mark— suggesting that any perceived mark-directed behaviours observed could be a part of general preening behaviour. These authors conclude that under their
paradigm In science and philosophy, a paradigm ( ) is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field. The word ''paradigm'' is Ancient ...
, house crows do not appear to pass the mark test, but also emphasize the high level of variability in results from the mark test and the necessity for testing to be done with larger sample sizes. * Some pigeons can pass the mirror test after training in the prerequisite behaviors. In 1981, American psychologist B. F. Skinner found that pigeons are capable of passing a highly modified mirror test after extensive training. In the experiment, a pigeon was trained to look in a mirror to find a response key behind it, which the pigeon then turned to peck to obtain food. Thus, the pigeon learned to use a mirror to find critical elements of its environment. Next, the pigeon was trained to peck at dots placed on its feathers; food was, again, the consequence of touching the dot. The latter training was accomplished in the absence of the mirror. The final test was placing a small bib on the pigeon—enough to cover a dot placed on its lower belly. A control period without the mirror present yielded no pecking at the dot. When the mirror was revealed, the pigeon became active, looked in the mirror and then tried to peck on the dot under the bib. However, untrained pigeons have never passed the mirror test.


Fish

* Bluestreak cleaner wrasse (''Labroides dimidiatus''): According to a study done in 2019, cleaner wrasses were the first fish observed to pass the mirror test. The bluestreak cleaner wrasse is a tiny tropical reef cleaner fish. Cleaner fish have an adapted evolutionary behavior in which they remove parasites and dead tissue from larger fish. When put through the mirror test, using a benign brown gel injected into the skin of the fish, and resembling a parasite, the cleaner wrasse showed all the behaviors of passing through the phases of the test. When provided with a colored tag in a modified mark test, the fish attempted to scrape off this tag by scraping their bodies on the side of the mirror. Gordon Gallup believes the cleaner wrasses' behavior can be attributed to something other than recognizing itself in a mirror. Gallup has argued that a cleaner wrasse's job in life is to be aware of ectoparasites on the bodies of other fish, so it would be hyper aware of the fake parasite that it noticed in the mirror, perhaps seeing it as a parasite that it needed to clean off of a different fish. The authors of the study retort that because the fish checked itself in the mirror before and after the scraping, this means that the fish has self-awareness and recognizes that its reflection belongs to its own body. The cleaner wrasses, when tested, spent a large amount of time with the mirror when they were first getting acquainted with it, without any training. Importantly, the cleaner wrasses performed scraping behavior with the colored mark, and they did not perform the same scraping behavior without the colored mark in the presence of the mirror, nor when they were with the mirror and had a transparent mark. Following various objections, the researchers published a follow-up study in 2022, where they did the mirror test on a larger sample of wrasses and experimented with several marking techniques. The new results "increase he researchers'confidence that cleaner fish indeed pass the mark test", although wrasses attempted to scrape off the mark only when it resembled a parasite. Another study in 2024 found that cleaner wrasse that initially showed aggression to photographs 10% larger and 10% smaller than themselves ceased confrontation with 10% larger photographs upon encountering their reflection. * Giant oceanic manta ray (''Mobula birostris''): In 2016 a modified mirror test done on two captive manta rays showed that they exhibited behavior associated with
self-awareness In philosophy of self, philosophy, self-awareness is the awareness and reflection of one's own personality or individuality, including traits, feelings, and behaviors. It is not to be confused with consciousness in the sense of qualia. While ...
(i.e. contingency checking and unusual self-directed behavior).


Crustaceans

* Atlantic ghost crab (''Ocypode quadrata''): A 2023 study found that these crabs seem to be capable of recognizing themselves in a mirror. The study's author concluded that the data indicate that the crabs have "a rudimentary form of self-awareness". Cephalopods * Mimic octopus (''Thaumoctopus mimicus''): A video in 2025 showed a Mimic Octopus recognising itself in a mirror.


Insects

* Myrmica rubra, Myrmica ruginodis, and Myrmica sabuleti: A 2015 study found that individuals ants of these three ant species would attempt to clean themselves after being exposed to a mirror and seeing a blue dot on their bodies.


Animals that have failed

Some animals that have reportedly failed the classic MSR test include:


Mammals


= Carnivorans

= *
Sea lion Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. ...
s (''Zalophus californianus'') *
Giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear or simply panda, is a bear species endemic to China. It is characterised by its white animal coat, coat with black patches around the eyes, ears, legs and shoulders. ...
(''Ailuropoda melanoleuca''): In one study, 34 captive giant pandas of a wide range of ages were tested. None of the pandas responded to the mark and many reacted aggressively towards the mirror, causing the researchers to consider the pandas viewed their reflection as a
conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...
. *
Dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...
s (''Canis lupus familiaris''): Dogs either treat the image as another animal, or come to ignore it completely.


= Primates

= * Stump-tailed macaque (''Macaca arctoides'') *
Crab-eating macaque The crab-eating macaque (''Macaca fascicularis''), also known as the long-tailed macaque or cynomolgus macaque, is a cercopithecine primate native to Southeast Asia. As a synanthropic species, the crab-eating macaque thrives near human settlem ...
(''Macaca fascicularis'') * Black-and-white colobus (''Colobus guereza'') *
Hamadryas baboon The hamadryas baboon (''Papio hamadryas'' ; gawina;Aerts 2019 , Ar Robbaḥ) is a species of baboon within the Old World monkey family. It is the northernmost of all the baboons, being native to the Horn of Africa and the southwestern region o ...
(''Papio hamadryas'') *
Cotton-top tamarin The cotton-top tamarin (''Saguinus oedipus'') is a small New World monkey weighing less than . This New World monkey can live up to 24 years, but most of them die by 13 years. One of the smallest primates, the cotton-top tamarin is easily reco ...
(''Saguinus oedipus'') *
Chacma Baboon The chacma baboon (''Papio ursinus''), also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide vari ...
(Papio Ursius)


Birds

* Grey parrot *
New Caledonian crow The New Caledonian crow (''Corvus moneduloides'') is a medium-sized member of the family Corvidae, native to New Caledonia. The bird is often referred to as the 'qua-qua' due to its distinctive call. It eats a wide range of food, including many t ...
*
Jackdaw Jackdaws are two species of bird in the genus ''Coloeus'' closely related to, but generally smaller than, crows and ravens ('' Corvus''). They have a blackish crown, wings, and tail, with the rest of their plumage paler.Madge & Burn (1994) 136� ...
*
Great tit The great tit (''Parus major'') is a small passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central Asia and east across the Palearctic to the Amur River, south to parts of No ...
(''Parus major'')


Fish

*The Tanganyikan cichlid, or daffodil cichlid ('' Neolamprologus pulcher''), is another fish that has failed the mirror test, according to a study done in 2017. Although not cleaner fish like the cleaner wrasses, these fish are typically regarded as socially intelligent and can recognize conspecifics in their social groups. Therefore, they would theoretically make good candidates for the mirror test, but they ended up failing. Similar to the cleaner wrasse, the Tanganyikan cichlid first exhibited signs of aggression towards the mirrored image. After a colored mark was injected, the researchers found no increased scraping or trying to remove the mark, and the cichlids did not observe the side with the mark any longer than it would have otherwise. This demonstrates a lack of contingency checking and means that the Tanganyikan cichlid did not pass the mirror test.


Cephalopods

* Octopodes oriented towards their image in a mirror, but no difference in their behaviour (as observed by humans) was seen in this condition when compared with a view of other octopodes.


Animals that may pass


Mammals


= Primates

=
Gibbon Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical forests from eastern Bangladesh and Northeast Indi ...
(g. ''Hylobates'', ''Symphalangus'' and ''Nomascus'') have failed to show self-recognition in at least two tests. However, modified mirror tests with three species of
gibbon Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical forests from eastern Bangladesh and Northeast Indi ...
s (''Hylobates syndactylus'', ''H. gabriellae'', ''H. leucogenys'') in 2000 showed convincing evidence of self-recognition even though the animals failed the standard version of the mirror test. Another study published in 2009 documents 12 cases of spontaneous self-recognition in front of the mirror by a pair of
siamang The siamang (, ; ''Symphalangus syndactylus'') is an endangered arboreal, black-furred gibbon native to the forests of Indonesia, Malaysia, and Thailand. The largest of the gibbons, the siamang can be twice the size of other gibbons, reaching i ...
s (Symphalangus syndactylus).
Capuchin monkey The capuchin monkeys () are New World monkeys of the subfamily Cebinae. They are readily identified as the "Street organ, organ grinder" monkey, and have been used in many movies and television shows. The range of capuchin monkeys includes some t ...
(''Cebus apella'') did not pass in one test but recognized the reflection as special in another.
Rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies split between two groups, the Chinese-derived and the Indian-derived. Generally brown or g ...
(''Macaca mulatta'') Though macaques failed the original mark test, they have been reported to exhibit other behaviours that indicate self-recognition. Rhesus macaques have been observed to use mirrors to study otherwise-hidden parts of their bodies, such as their genitals and implants in their heads. It has been suggested this demonstrates at least a partial self-awareness, although further study is needed.


= Pigs

= Pigs can use visual information seen in a mirror to find food. In a 2009 experiment, seven of the eight pigs who spent 5 hours with a mirror were able to find a bowl of food hidden behind a wall and revealed using a mirror. Pigs that had no experience with mirrors, looked behind the mirror for the food. BBC Earth also showed the food bowl test, and the "matching shapes to holes" test, in the ''Extraordinary Animals'' series. There is evidence of self-recognition when presented with their reflections. So far, pigs have not been observed to pass the mirror mark test, however.


Birds

Adelie penguins do not react as if they would react to a wild bird, and when presented with a mirror, gestured as if they recognized themselves. However, they were not bothered enough by marks on their face to notice.


Fish

Two captive giant manta rays showed frequent, unusual and repetitive movements in front of a mirror, suggesting contingency checking. They also showed unusual self-directed behaviors when exposed to the mirror. Manta rays have the largest brains of all fish. In 2016, Csilla Ari tested captive manta rays at the Atlantis Aquarium in the Bahamas by exposing them to a mirror. The manta rays appeared to be extremely interested in the mirror. They behaved strangely in front the mirror, including doing flips and moving their fins. They also blew bubbles. They did not interact with the reflection as if it were another manta ray; they did not try to socialize with it. However, only an actual mirror test can determine if they actually recognize their own reflections, or if they are just demonstrating exploratory behavior. A classic mirror test has yet to be done on manta rays. Another fish that may pass the mirror test is the common archerfish, '' Toxotes chatareus''. A study in 2016 showed that archerfish can discriminate between human faces. Researchers showed this by testing the archerfish, which spit a stream of water at an image of a face when they recognized it. The archerfish would be trained to expect food when it spat at a certain image. When the archerfish was shown images of other human faces, the fish did not spit. They only spit for the image that they recognized. Archerfish normally, in the wild, use their spitting streams to knock down prey from above into the water below. The study showed that archerfish could be trained to recognize a three-dimensional image of one face compared to an image of a different face and would spit at the face when they recognized it. The archerfish were even able to continue recognizing the image of the face even when it was rotated 30, 60 and 90°.


Humans

The rouge test is a version of the mirror test used with human children. Using rouge makeup, an experimenter surreptitiously places a dot on the face of the child. The children are then placed in front of a mirror and their reactions are monitored; depending on the child's development, distinct categories of responses are demonstrated. This test is widely cited as the primary measure for mirror self-recognition in human children.Sedikides, C. & Spencer, S.J. (Eds.) (2007). ''The Self''. New York: Psychology Press There is criticism that passing a rouge test may be culturally motivated, and that what is commonly thought about mirror self-recognition actually applies only to children of Western countries. A study from 2010 tested children from rural communities in Kenya, Fiji, Saint Lucia, Grenada and Peru, as well as urban United States and rural Canada. The majority of children from the US and Canada passed the MSR test, but fewer children from the other regions passed the MSR test. In the Kenya test, only 3% of children aged 18–72 months touched the mark. In the Fiji test, none of the children aged 36–55 months touched the mark. The other non-Western rural children scored much better, but still markedly worse than their Western counterparts.


Developmental reactions

In a study in 1972, from the ages of 6 to 12 months, children typically saw a "sociable playmate" in the mirror's reflection. Self-admiring and embarrassment usually began at 12 months, and at 14 to 20 months, most children demonstrated avoidance behaviors. By 20 to 24 months, self-recognition climbed to 65%. Children did so by evincing mark-directed behavior; they touched their own noses or tried to wipe the marks off. In another study, in 1974, at 18 months, half of children recognized the reflection in the mirror as their own. Self-recognition in mirrors apparently is independent of familiarity with reflecting surfaces. In some cases, the rouge test has been shown to have differing results, depending on sociocultural orientation. For example, a Cameroonian Nso sample of infants 18 to 20 months of age had an extremely low amount of self-recognition outcomes at 3.2%. The study also found two strong predictors of self-recognition: object stimulation (maternal effort of attracting the attention of the infant to an object either person touched) and mutual eye contact. A strong correlation between self-concept and
object permanence Object permanence is the understanding that whether an object can be sensed has no effect on whether it continues to exist. This is a fundamental concept studied in the field of developmental psychology, the subfield of psychology that addres ...
have also been demonstrated using the rouge test.


Implications

The rouge test is a measure of
self-concept In the psychology of self, one's self-concept (also called self-construction, self-identity, self-perspective or self-structure) is a collection of beliefs about oneself. Generally, self-concept embodies the answer to the question ''"Who am I? ...
; the child who touches the rouge on their own nose upon looking into a mirror demonstrates the basic ability to understand self-awareness. Animals, young children, and people who have gained sight after being blind from birth, sometimes react to their reflection in the mirror as though it were another individual. Theorists have remarked on the significance of this period in a child's life. For example,
psychoanalyst PsychoanalysisFrom Greek: and is a set of theories and techniques of research to discover unconscious processes and their influence on conscious thought, emotion and behaviour. Based on dream interpretation, psychoanalysis is also a talk th ...
Jacques Lacan Jacques Marie Émile Lacan (, ; ; 13 April 1901 – 9 September 1981) was a French psychoanalyst and psychiatrist. Described as "the most controversial psycho-analyst since Sigmund Freud, Freud", Lacan gave The Seminars of Jacques Lacan, year ...
used a similar test in marking the mirror stage when growing up.Lacan, J., ''Some reflections on the Ego'' in ''Écrits'', org. published 1949. Current views of the self in psychology position the self as playing an integral part in human motivation, cognition, affect, and
social identity Identity is the set of qualities, beliefs, personality traits, appearance, or expressions that characterize a person or a group. Identity emerges during childhood as children start to comprehend their self-concept, and it remains a consistent ...
.


Robots

In 2012, early steps were taken to make a
robot A robot is a machine—especially one Computer program, programmable by a computer—capable of carrying out a complex series of actions Automation, automatically. A robot can be guided by an external control device, or the robot control, co ...
pass the mirror test.


See also

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Animal consciousness Animal consciousness, or animal awareness, is the Quality (philosophy), quality or state of self-awareness within an animal, or of being aware of an external object or something within itself. In humans, consciousness has been defined as: senti ...
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Cognitive tests Cognitive tests are assessments of the cognitive capabilities of humans and other animals. Tests administered to humans include various forms of IQ tests; those administered to animals include the mirror test (a test of visual self-awareness) and t ...
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Embodied cognition Embodied cognition represents a diverse group of theories which investigate how cognition is shaped by the bodily state and capacities of the organism. These embodied factors include the motor system, the perceptual system, bodily interactions wi ...
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Face perception Facial perception is an individual's understanding and interpretation of the face. Here, perception implies the presence of consciousness and hence excludes automated facial recognition systems. Although facial recognition is found in other spe ...
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Self-agency Self-agency, also known as the phenomenal will, is the sense that actions are self-generated. Scientist Benjamin Libet was the first to study it, concluding that brain activity predicts the action before one even has conscious awareness of his ...
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Visual perception Visual perception is the ability to detect light and use it to form an image of the surrounding Biophysical environment, environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual percept ...
*
Visual system The visual system is the physiological basis of visual perception (the ability to perception, detect and process light). The system detects, phototransduction, transduces and interprets information concerning light within the visible range to ...


References


External links


List of animals who passed the mirror test and promising candidates on animalcognition.org (Wayback Machine)

The World First Self-Aware Robot and the Success of Mirror Image Cognition
(Lecture at the Karlsruhe University and the Munich University, Germany), 8 November 2006.


Elephants' jumbo mirror ability (BBC News)
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* ttp://www.conscious-robots.com/2010/01/08/can-a-robot-pass-the-mirror-test/ Can a robot pass the mirror test? – Raúl Arrabales Moreno 2010-01-08 * {{DEFAULTSORT:Mirror Test Cognitive tests Consciousness Mirrors Perception Self Articles containing video clips 1970 in science