Neoteny

For the topic of soil formation, see Pedogenesis.

human body proportion changes with age

Toy dogs often display an extreme level of neoteny, resembling not just infant, but fetal wolves.^[1]

Neoteny ( /niːˈɒtɨniː/), also called juvenilization or pedomorphism^[2], is the retention, by adults in a species, of traits previously seen only in juveniles, and is a subject studied in the field of developmental biology. In neoteny, the physiological (or somatic) development of an animal or organism is slowed or delayed.^[3] Ultimately this process results in the retention, in the adults of a species, of juvenile physical characteristics well into maturity and pedogenesis (paedogenesis), the reproduction in a neotenized state.^[4]

Neoteny is one of three dimensions of heterochrony, or the change in timing of developmental events: acceleration (faster) vs. neoteny (slower), hypermorphosis (further) vs. progenesis (not as far), and predisplacement (begins earlier) vs. postdisplacement (begins later).^[5]

The word neoteny is borrowed from the German Neotenie, the latter constructed from the Greek νέος (neos, young) and τείνειν (teínein, tend to). The adjectival form of the word is either "neotenous" or "neotenic".^[6] The opposite of neoteny is either called "gerontomorphic"^[7] or "peramorphic"^[8].

In humans

Neotenous traits in humans

Physical anthropologist Barry Bogin considers Betty Boop to be an example of neoteny.[9]

These are neotenous traits in humans: flattened face, ^[2] broadened face,^[10] large brain,^[2] hairless body,^[2] hairless face,^[11] small nose,^[11] reduction of brow ridge,^[2] small teeth,^[2] small upper jaw (maxilla),^[2] small lower jaw (mandible),^[2] epicanthic eye fold^[10] (present in all people in the embryonic stage),^[12] thinness of skull bones,^[10] limbs proportionately short compared to torso length,^[10] longer leg than arm length, and^[13] upright stance.^{[12] [7]}

Human evolution

Main article: human evolution

Stephen Jay Gould believed that the "evolutionary story" of humans is one where we have been "retaining to adulthood the originally juvenile features of our ancestors".^[14] J.B.S. Haldane mirrors Gould's hypothesis by stating a "major evolutionary trend in human beings" is "greater prolongation of childhood and retardation of maturity."^[2]

Delbert D. Thiessen claimed that "neoteny becomes more apparent as early primates evolved into later forms" and that primates have been "evolving toward flat face."^[15] Stephen Jay Gould argued "that the whole enterprise of ranking groups by degree of neoteny is fundamentally unjustified." (Gould, 1996, pg. 150).^[16]

In opposition, M.J. Rantala does not believe neoteny has been the main cause of human evolution, because humans only retain some juvenile traits while relinquishing others.^[17] He claims the high leg-to-body ratio (long legs) of adult humans as opposed to human infants shows that there is not holistic trend in humans towards neoteny when compared to the other Great Apes.^[17]

Australian anthropologist Andrew Arthur Abbie agrees, citing the gerontomorphic fleshy human nose and long human legs as contradicting the neoteny hominid evolution hypothesis, although he does believe humans are generally neotenous.^[7] Brian Keith Hall also cites the long legs of humans as a peramorphic trait in sharp contrast to neoteny.^[8]

Between sexes

Ashley Montagu notes the following neotenous traits in women relative to men: more delicate skeleton, smoother ligament attachments, smaller mastoid processes, reduced brow ridges, more forward tilt of the head, narrower joints, less hairy, more delicate skin, retention of fetal body hair, smaller body size, more backward tilt of pelvis, greater longevity, lower basal metabolism, faster heartbeat, greater extension of development periods, higher pitched voice and larger tears.^[2]

Attractive women's faces

Main article: physical attractiveness

In a cross-cultural study, more neotenized female faces were found to be most attractive to men while less neotenized female faces were found to be less attractive to men, regardless of the females' actual age.^[18] Michael R. Cunningham of the Department of Psychology at the University of Louisville found, using a panel of "Asian", "Hispanic" and "White" judges, that the Asian, Hispanic and White female faces found most attractive were those that had "neonate large eyes, greater distance between eyes, and small noses"^[19] and his study led him to conclude that "large eyes" were the most "effective" of the "neonate cues".^[19] Cunningham also said that "shiny" hair may be indicative of "neonate vitality".^[19]

Cunningham noted a "difference" in the preferences of Asian and White judges with Asian judges preferring women with "less mature faces" and smaller mouths than the White judges.^[19] Cunningham hypothesized that this difference in preference may stem from "ethnocentrism" since "Asian faces possess those qualities", so Cunningham re-analyzed the data with "11 Asian targets excluded" and concluded that "ethnocentrism was not a primary determinant of Asian preferences."^[19] Using a panel of "Blacks" and "Whites" as judges, Cunningham found more neotenous faces were perceived as having both higher "femininity" and "sociability".^[19]

In contrast, Cunningham found that faces that were "low in neoteny" were judged as "intimidating".^[19] Upon analyzing the results of his study Cunningham concluded that preference for "neonate features may display the least cross-cultural variability" in terms of "attractiveness ratings".^[19] In a study of Italian women who have won beauty competitions, it was found that the Italian women who won the beauty competitions had faces characterized by more "babyness" traits compared to the "normal" women used as a reference.^[20] In a study of 60 Caucasian female faces at the University of St. Andrews, it was found that the average facial composite of the 15 faces found most attractive differed from the facial composite of the whole by: a reduced lower facial region, a thinner jaw and a higher forehead.^[21]

Between races and among primates

Ashley Montagu claims human skulls are more neotenized than Neanderthal skulls.^[2]

Paleontologist Stephen Jay Gould who taught biology and evolution at New York University objected to the ranking of races as more or less neotenous. But Gould argued that if one used the terms set forth by 1920s proponents of racial neoteny, "Orientals", not whites, are "clearly" the most neotenized human race.^[16]

Ashley Montagu mirrored this statement when he stated that the "Mongoloid skull, whether Chinese or Japanese" is the most neotenized human skull.^[2] Ashley Montagu further claimed that the "European" skull was less neotenized than the Mongoloid, with the "Australian Aborigine" skull less neotenized than the European and the Neanderthal skull even less neotenized than the Australian Aborigine skull.^[2] Ashley Montagu claimed that humans have more neotenized skulls than Australopithecus.^[22]

Delbert D. Thiessen claimed that Homo Sapiens are more neotenized than Homo Erectus, Homo Erectus was more neotenized than Australopithicus, Great Apes are more neotenized than Old World monkeys and Old World monkeys are more neotenized than New World monkeys.^[15]

Nancy Lynn Barrickman of the Department of Evolutionary Psychology at Duke University claimed Brian T. Shea found by multivariate analysis that Bonobos are more neotenized than the common chimpanzee, taking into account such features as the proportionately long torso length of the Bonobo.^[23] Ashley Montagu believed that part of the differences seen in the morphology of "modernlike types of man" can be attributed to different rates of "neotenous mutations" in their early populations.^[24]

Mongoloids

Main article: Mongoloid

Heh Miao woman (1911)

According to Ashley Montagu who taught anthropology at Princeton University, "The Mongoloid skull has proceeded further than in any other people."^[2] "The Mongoloid skull, whether Chinese or Japanese, has been rather more neotenized than the Caucasoid or European."^[2] "The female skull, it will be noted, is more pedomorphic in all human populations than the male skull."^[2]

In Ashley Montagu's list of "[n]eotenous structural traits in which Mongoloids... differ from Caucasoids", Montagu lists "Larger brain, larger braincase, broader skull, broader face, flat roof of the nose, inner eye fold, more protuberant eyes, lack of brow ridges, greater delicacy of bones, shallow mandibular fossa, small mastoid processes, stocky build, persistence of thymus gland into adult life, persistence of juvenile form of zygomatic muscle, persistence of juvenile form of superior lip muscle, later eruption of full dentition (except second and third molars), less hairy, fewer sweat glands, fewer hairs per square centimeter [and] long torso".^[2]

According to Clive Bromhall who has a Ph.D. in zoology from Oxford University, "Mongoloid races are explained in terms of being the most extreme pedomorphic humans."^[25]

Richard Grossinger, professor of anthropology at University of Maine at Portland, claimed "The intuition that advanced human development was pedomorphic rather than recapitulationary and accelerated was disturbing to many Eurocentric nineteenth century anthropologists."^[26] "If juvenilization was the characteristic for advanced status, then it was clear that the Mongoloid races were more deeply fetalized in most respects and thus capable of the greatest development."^[26]

Stephen Oppenheimer of the Institute of Cognitive & Evolutionary Anthropology at Oxford University claimed "An interesting hypothesis put forward by paleontologist Stephen Jay Gould many years ago was that the package of the Mongoloid anatomical changes could be explained by the phenomenon of neoteny, whereby an infantile or childlike body form is preserved in adult life. Neoteny in hominids is still one of the simplest explanations of how we developed a disproportionately large brain so rapidly over the past few million years. The relatively large brain and the forward rotation of the skull on the spinal column, and body hair loss, both characteristic of humans, are found in foetal chimps. Gould suggested a mild intensification of neoteny in Mongoloids, in whom it has been given the name pedomorphy. Such a mechanism is likely to involve only a few controller genes and could therefore happen over a relatively short evolutionary period. It would also explain how the counterintuitive retrousse [turned up at the end] nose and relative loss of facial hair got into the package."^[27] "[D]ecrease unnecessary muscle bulk, less tooth mass, thinner bones and smaller physical size; ...this follows the selective adaptive model of Mongoloid evolution."^[27]

Bushmen

Main article: Bushmen

According to Ashley Montagu, Bushmen have the following neotenous traits relative to Caucasoids: "large brain", light skin pigment, less hairy, round-headed, bulging forehead, small cranial sinuses, flat roof of the nose, small face, small mastoid processes, wide eye separation, median eye fold, short stature and horizontal penis.^[2]

Negroids

Women of Equatorial Africa

Main article: Negroid

According to Ashley Montagu, Negroids have the following neotenous traits relative to Caucasoids: flattish nose, flat roof of the nose, small ears, narrower joints, frontal skull eminences, later closure of the premaxillary sutures, less hairy, longer eyelashes and cruciform pattern of the lower second and third molars.^[2]

Psychology

See also: memory and aging

Humans have been evolving toward greater "psychological-neoteny".^[28] Highly-educated people and eminent scientists usually demonstrate more neotenous psychological traits,^[29] and students with more of a "baby face" tend to "outperform" their less-neotenized peers in school.^[30] In fact, the ability of an adult human to learn has long been considered a neotenous trait.^[31] Physical neotenization in humans has, likewise, caused psychologically neotenous traits in humans: curiosity, playfulness, affection, sociality and an innate desire to cooperate.^[32]

Specific neotenies

Populations with a history of dairy farming have evolved to be lactose tolerant in adulthood whereas other populations generally lose the ability to break down lactose as they grow into adults. ^[33]

Down syndrome

Down syndrome neotenizes the brain and body to the fetal state.^[34] Down syndrome is characterized by decelerated maturation (neoteny), incomplete morphogenesis (vestigia) and atavisms.^[35] Dr. Weihs considers Down syndrome to be a condition of "neoteny" that makes people "like a baby."^[36]

He notes both the physical neoteny of people with Down syndrome: "round in shape," "bowed legs which tend to be short," "slanty eyes," a "long tongue" and "short fingers," and their mental neoteny: "unsexual," "playful," "affectionate," "mischievous" and "imitative".^[36]

Anime and manga

See also: cuteness in Japanese culture

Dr. Thomas Lamarre, professor of East Asian Studies and Art History at McGill University, claimed that after World War II Japanese people as shown in their manga (漫画^?) and anime (アニメ^?) became "fascinated" with "neoteny" and "cuteness".^[37]

In other species

• The axolotl is a salamander that retains its juvenile aquatic form throughout adulthood and tiger salamander and Rough-skinned Newt can both retain gills into adulthood.^[38]
• flightless birds' physical proportions resemble those of the chicks of flighted birds;
• A plant species in the genus Oreostylidium neotenized to become mature earlier than other species in its genus in response to selective pressure.^[39]

Domestication

Domestication has involved selection for behavioral characteristics that characterize young animals so, since "behavior is rooted in biology", domestication has resulted in an array of similar neotenous physical traits having arisen in various domesticated animals.^[40] Such neotenous physical traits in domesticated animals such as dogs, pigs, cats, and recently foxes are floppy ears, changes in reproductive cycle, curly tails, piebald coloration, fewer or shortened vertebra,^[40] large eyes, rounded forehead, large ears and shortened muzzle.^[41]

See also

• Cuteness
• Sexual selection
• Ageing

References

1. ^ Budiansky, Stephen (1999). The Covenant of the Wild: Why animals chose domestication. Yale University Press. ISBN 0300079931. 
2. ^ ^{a b c d e f g h i j k l m n o p q r s} Montagu, A. (1989). Growing Young. Bergin & Garvey: CT.
3. ^ Ridely, M. Evolution. Neoteny. 1985. http://www.blackwellpublishing.com/ridley/a-z/Neoteny.asp
4. ^ Schell, S. C., Handbook of Trematodes of North America North of Mexico 1985 pg. 22
5. ^ Rice, S. H. "Heterochrony". November 2007. Accessed July 14, 2011.
6. ^ The Free Dictionary. "Neotenous". 2011. Accessed April 30, 2011, from http://www.thefreedictionary.com/neotenous
7. ^ ^{a b c} Henke, W. (2007). Handbook of paleoanthropology, Volume 1. Springer Books, NY.
8. ^ ^{a b} Hall, B.K., Hallgrímsson, B. Monroe, W.S. (2008). Strickberger's evolution: the integration of genes, organisms and populations. Jones and Bartlett Publishers: Canada.
9. ^ Bogin, B. (1999). Patterns of Human Growth. Cambridge University Press, NY.
10. ^ ^{a b c d} Gould, S.J. (1977) Ontogeny and Phylogeny, Cambridge: Belknap Press.
11. ^ ^{a b} Jean-Baptiste de Panafieu, P. (2007). Evolution. Seven Stories Press, USA.
12. ^ ^{a b} Hetherington, R. (2010). The Climate Connection: Climate Change and Modern Human Evolution. Cambridge University Press.
13. ^ Smith, J.M. (1958). The theory of evolution. Cambridge University Press.
14. ^ Gould, S.J. A BIOLOGICAL HOMAGE TO MICKEY MOUSE.
15. ^ ^{a b} Thiessen, D.D. (1997). Bittersweet destiny: the stormy evolution of human behavior. Transaction Publishers, N.J.
16. ^ ^{a b} Gould, S.J. (1996). The mismeasure of man. W.W. Norton and Company, N.Y.
17. ^ ^{a b} Rantala, M.J. (2006). Evolution of nakedness in Homo sapiens. In Zoology.
18. ^ Jones, D. Sexual Selection, Physical Attractiveness and Facial Neoteny: Cross-Cultural Evidence and Implications. p.723
19. ^ ^{a b c d e f g h} Cunningham, M., Roberts, A., & Vu, C. (1995). “Their ideas of beauty are, on the whole, the same as ours”: consistency and variability in the cross-cultural perception of female physical attractiveness. Journal of Personality and Social Psychology, 68, 261-79. doi: 10.1037/0022-3514.68.2.261
20. ^ Chiarella Sforza, Alberto Laino, Raoul D'Alessio, Gaia Grandi, Miriam Binelli and Virgilio Ferruccio Ferrario (2009) Soft-Tissue Facial Characteristics of Attractive Italian Women as Compared to Normal Women. The Angle Orthodontist: January 2009, Vol. 79, No. 1, pp. 17-23.
21. ^ Perrett, D.I., May, K.A. & Yoshikawa, S. 1994. Facial shape and judgements of female attractiveness. Nature 368: 239-242.
22. ^ Montagu, A. Time, Morphology, and Neoteny in the Evolution of Man.
23. ^ Barrickman, N.T. (2008). Evolutionary Relationship Between Life History and Brain Growth in Anthropoid Primates. Retrieved Jun 1, 2011, from dukespace.lib.duke.edu/dspace/.../D_Barrickman_Nancy_a_200812.pdf?.
24. ^ M. F. Ashley Montagu. Time, Morphology, and Neoteny in the Evolution of Man. In American Anthropologist, Volume 57, Issue 1 (February 1955) Pages: 13-27
25. ^ Moxon, Steve. The Eternal Child: An Explosive New Theory of Human Origins and Behaviour by Clive Bromhall Ebury Press, 2003. [1]
26. ^ ^{a b} Grossinger, Richard. Embryogenesis. Published by North Atlantic Books, 2000 ISBN 1-55643-359-X
27. ^ ^{a b} Oppenheimer, Stephen. The Real Eve. Published by Carroll & Graf Publishers, 2003 ISBN 0-7867-1192-2
28. ^ Charlton BG. The rise of the boy-genius: psychological neoteny, science and modern life. Medical Hypotheses. 2006; 67: 679-81
29. ^ See Charlton BG, The rise of the boy-genius: psychological neoteny, science and modern life. Medical Hypotheses. 2006; 67: 679–81.
30. ^ Zebrowitz, L. A., Andreoletti, C., Collins, M. A., Lee, S. Y., & Blumenthal, J. (1998). Bright, bad, babyfaced boys: Appearance stereotypes do not always yield self-fulfilling prophecy effects. Journal of Personality & Social Psychology, 75, 1300-1320.
31. ^ Young J.Z. 1957; 2nd ed 1975. The life of mammals. Oxford.
32. ^ Lehman, A. (2010). Evolution, Autism and Social Change. neoteny.org.
33. ^ Johnson, S. Religion, Science and other Neotenous Behaviour. www.ugr.es/~sam/index_archivos/Essays/Neoteny.pdf
34. ^ Opitz, John M. & Gilbert-Barness, Enid F. (1990) Reflections on the Pathogenesis of Down Syndrome. American Journal of Medical Genetics 7: p. 44
35. ^ Optiz, J.M. (1990). Reflections on the pathogenesis of Down syndrome. In American Journal of Medical Genetics Supplement. 7:38.
36. ^ ^{a b} Richards, M.C. Toward wholeness: Rudolf Steiner education in America. 1980. University Press of New England, N.H.
37. ^ Concordia University Fine Arts Department of Art History. "Comics, Japanese Popular Culture and Contemporary Art". Retrieved May 27, 2011, from howietsui.com/pdf/concordiaprogram.pdf
38. ^ C. Michael Hogan (2008) Rough-skinned Newt (Taricha granulosa), Globaltwitcher, ed. N. Stromberg [2]
39. ^ Wagstaff, S J; Wege, J (2002), "Patterns of diversification in New Zealand Stylidiaceae", American Journal of Botany 89 (5): 865–874, doi:10.3732/ajb.89.5.865, http://www.amjbot.org/cgi/content/full/89/5/865 .
40. ^ ^{a b} Trut, L. N. (1999). Early Canid Domestication: The Farm-Fox Experiment American Scientist. 87(2), 160-169.
41. ^ Bertone, J. (2006). Equine geriatric medicine and surgery. Saunders, MI.