Mirror test

From Wikipedia, the free encyclopedia

  (Redirected from Self-recognition)
Jump to: navigation, search
 This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (March 2009)

The mirror test is a measure of self-awareness developed by Gordon Gallup Jr. in 1970,[1][2] that was based in part on observations made by Charles Darwin.[3][4] While visiting a zoo, Darwin held a mirror up to an orangutan and recorded the animal's reaction, which included making a series of facial expressions. Darwin noted that the significance of these expressions was ambiguous, and could either signify that the primate was making expressions at what it perceived to be another animal, or it could be playing a sort of game with a new toy. There are nine species that pass the mirror test, including magpies and elephants but mostly primates. Most human babies do not pass the mirror test until several months of age.[3][4]

Gordon Gallup built on these observations by devising a test that attempts to gauge self-awareness by determining whether an animal can recognize its own reflection in a mirror as an image of itself. This is accomplished by surreptitiously marking the animal with two odourless dye spots. The test spot is on a part of the animal that would be visible in front of a mirror, while the control spot is in an accessible but hidden part of the animal's body. Scientists observe if the animal reacts in a manner consistent with it being aware that the test dye is located on its own body while ignoring the control dye. Such behaviour might include turning and adjusting of the body in order to better view the marking in the mirror, or poking at the marking on its own body with a limb while viewing the mirror.

At first, even animals that are capable of passing the mirror test respond as the orangutan described by Darwin.[4] In fact, young children and people who have been blind from birth but have their sight restored initially react as if their reflection in the mirror was another person.[3][4]

Contents

[edit] Animals that pass the mirror test

A dog's reaction to a mirror

Animals that have passed the mirror test are all of the great apes (bonobos[5], chimpanzees[5][6], orangutans[citation needed], gorillas[citation needed] and humans[4]), bottlenose dolphins[5][7][8], Orcas[citation needed], elephants[9], European Magpies[10], and pigs[11]. Initially, it was thought that gorillas did not pass the test, but there are now several well-documented reports (such as one gorilla, Koko[12]) of gorillas passing the test. In 1981, Epstein, Lanza and Skinner published a paper in the journal Science in which they argued that the pigeon also passes the mirror test.[13][14] Pigeons though could only detect the spots on their own body after they had been trained to and untrained pigeons have never been able to pass the mirror test.[15] However, magpies have been shown to pass the test by trying to remove a coloured sticker from underneath their beaks when shown it in a mirror.[16] Humans tend to fail the mirror test until they are about 18 months old, or the "mirror stage".[17] Dogs, cats, and young human children all fail the mirror test.[3][4]

Capuchin monkeys react to their reflection either with hostility or affection, although mark test experiments have shown that they are incapable of spontaneous mirror self-recognition.[18] Similar tests performed using video technology support these findings, but suggest that the monkeys possess the raw input systems required for explicit self-recognition.[19]

Pigs are also able to pass a variation of the mirror test. 7 of the 8 pigs tested were able to find a bowl of food hidden behind a wall using a mirror. The eighth pig looked behind the mirror for the food.[20]

[edit] Criticism of the mirror test

There is some debate as to the value and interpretation of results of the mirror test.[3][verification needed] While this test has been extensively conducted on primates, there is debate as to the value of the test as applied to animals who rely primarily on senses other than vision.[3][verification needed] Adaptations of the mirror test have been made in other modalities, such as scent. For instance, biologist Marc Bekoff developed a paradigm using dog urine for testing self-awareness in canines.[3][4]

[edit] See also

[edit] References

  1. ^ Gallup, GG Jr. (1970). "Chimpanzees: Self recognition". Science 167: 86–87. 
  2. ^ Psychologist May 1977
  3. ^ a b c d e f g Stanley Coren. How dogs think. ISBN 0743222326. 
  4. ^ a b c d e f g Archer, John (1992). Ethology and Human Development. Rowman & Littlefield. ISBN 0389209961. 
  5. ^ a b c Miller, Jason (2009), "Minding the Animals: Ethology and the Obsolescence of Left Humanism", American Chronicle, http://www.americanchronicle.com/articles/view/102661, retrieved 2009-05-21 
  6. ^ Povinelli, Daniel; de Veer, Monique; Gallup Jr., Gordon; Theall, Laura; van den Bos, Ruud. "An 8-year longitudinal study of mirror self-recognition in chimpanzees (Pan troglodytes)". Neuropsychologia 41 (2): 229–334. doi:10.1016/S0028-3932(02)00153-7. ISSN 0028-3932. 
  7. ^ "Intelligence and Humans". http://www.wiu.edu/users/emp102/DolphinWeb/dolphin_intel.html. Retrieved 2008-08-11. 
  8. ^ Marten, K. & Psarakos, S. (195). "Evidence of self-awareness in the bottlenose dolphin (Tursiops truncatus)". in Parker, S. T., Mitchell, R. & Boccia, M.. Self-awareness in Animals and Humans: Developmental Perspectives. Cambridge University Press. p. 361–379. http://earthtrust.org/delbook.html. Retrieved 2008-10-04. 
  9. ^ Joshua M. Plotnik, Frans B. M. de Waal, and Diana Reiss (2006) Self-recognition in an Asian elephant. Proceedings of the National Academy of Sciences 103(45):17053–17057 10.1073/pnas.0608062103 abstract
  10. ^ Prior, Schwarz, and Güntürkün, Helmut, Ariane, and Onur (2008). "Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition". PLoS Biology (Public Library of Science) 6: e202. doi:10.1371/journal.pbio.0060202. http://biology.plosjournals.org/archive/1545-7885/6/8/pdf/10.1371_journal.pbio.0060202-L.pdf. Retrieved 2008-08-21. 
  11. ^ http://dx.doi.org/10.1016/j.anbehav.2009.07.027
  12. ^ Francine Patterson and Wendy Gordon The Case for Personhood of Gorillas. In The Great Ape Project, ed. Paola Cavalieri and Peter Singer, St. Martin's Griffin, 1993, pp. 58-77.
  13. ^ Epstein, Lanza, & Skinner (1981), “Self-awareness” in the pigeon, Science 212:695-696
  14. ^ http://ww2.lafayette.edu/~allanr/selfaware.mpg is video of one such test
  15. ^ Frans B. M. de Waal. "The Thief in the Mirror". PLoS Biology (Public Library of Science). http://biology.plosjournals.org/perlserv/?request=get-pdf&file=10.1371_journal.pbio.0060201-L.pdf. Retrieved 2009-01-06. 
  16. ^ BBC News | Science & Environment | Meet the brains of the animal world
  17. ^ "Consciousness and the Symbolic Universe"
  18. ^ Roma, Peter; Silberberg, Alan; Huntsberry, Mary; Christensen, Chesley; Ruggiero, Angela; Suomi, Stephen (25 January 2007). "Mark tests for mirror self-recognition in capuchin monkeys (Cebus Apella) trained to touch marks.". American Journal of Primatology 69 (9): 989–1000. doi:10.1002/ajp.20404. ISSN 0275-2565. "The results are consistent with the finding that no monkey species is capable of spontaneous mirror self-recognition.". 
  19. ^ Anderson, James; Kuroshima, Hika; Paukner, Annika; Fujita, Kazuo (24 June 2008). "Capuchin monkeys (Cebus apella) respond to video images of themselves.". Animal Cognition 12 (1): 55–62. doi:10.1007/s10071-008-0170-3. ISSN 1435-9448. "Although they showed no signs of explicit self-recognition, the monkeys' behaviour strongly suggests recognition of the correspondence between kinaesthetic information and external visual effects.". 
  20. ^  

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/Mirror_test"