Averageness

In physical attractiveness studies, averageness is a characteristic of physical beauty in which the average phenotype (outward appearance) of the individual is found to be most attractive. The majority of averageness studies have focused on photographic overlay studies of human faces, in which images are morphed together.

A possible evolutionary explanation for averageness is koinophilia, in which sexually-reproducing animals seek mates with average features because extremes may indicate disadvantageous mutations. Like-attracts-like is not a workable explanation, as it would result in assortative mating rather than averageness.[1][2]

Other factors involved in measuring attractiveness are symmetry and youthfulness.[1][2]

History

Francis Galton, cousin of Charles Darwin, devised a technique called composite photography, which he believed could be used to identify 'types' by appearance, which he hoped would aid medical diagnosis, and even criminology through the identification of typical criminal faces. Galton's hypothesis was that certain groups of people may have common facial characteristics. To test the hypothesis, he created photographic composite images of the faces of vegetarians and criminals to see if there was a typical facial appearance for each. Galton overlaid multiple images of faces onto a single photographic plate so that each individual face contributed roughly equally to a final composite face. The resultant “averaged” faces did little to allow the a priori identification of either criminals or vegetarians, failing Galton's hypothesis. However, unexpectedly Galton observed that the composite image was more attractive than the component faces. Galton published this finding in 1878,[3] and also described his composite photography technique in detail in Inquiries in Human Faculty and its Development.[4]

Similar observations were made in 1886 by Stoddard, who created composite faces of members of the National Academy of Sciences and graduating seniors of Smith College.[5]

This phenomenon is now known as "averageness-effect", that is highly physically attractive tend to be indicative of the average traits of the population.

Despite the novelty of these findings, Galton and Stoddard's observations were forgotten for over a century.

Research

A University of Toronto study found that the facial proportions of celebrities including Jessica Alba were close to the average of all female profiles.[6]

In 1990, one of the first computer-based photographic attractiveness rating studies was conducted. During this year psychologists Langlois and Roggman wanted to systematically examine whether mathematical averageness is linked with facial attractiveness.[7][8][9][10][11][12][13] To test this, they selected photographs of 192 male and female Caucasian faces; each of which was computer scanned and digitized. They then made computer-processed composites of each image, as 2-, 4-, 8-, 16-, and 32-face composites, averaged by pixel. These faces, as well as the component faces, were rated for attractiveness by 300 judges on a 5-point Likert scale (1 = very unattractive, 5 = very attractive). The 32-composite face was the most visually attractive of all the faces.[7]

Many studies, using different averaging techniques, including the use of line drawings[14] and face profiles,[15] have shown that this is a general principle: average faces are consistently more attractive than the faces used to generate them.[16][17][18][19] Furthermore if a female composite (averaged) face made of 32 different faces is overlain with the face of an extremely attractive female model, the two images often line up closely, indicating that the model's facial configuration is very similar to the composite's.[20] See, for example, the illustration of Jessica Alba on the left.[17][18]

Transcending culture: Hadza people rated averaged Hadza faces as more attractive than actual faces from the tribe.

This principle transcends culture. For instance, Coren Apicella and her co-workers from Harvard University[21] created average faces of an isolated hunter-gatherer tribe of 1,000 in Tanzania, Africa, the Hadza people. Hadza people rated the averaged Hadza faces as more attractive than the actual faces in the tribe. While Europeans also rated average Hadza faces as attractive, the Hadza people expressed no preference for average European faces. Apicella[21] attributes this difference to the wider visual experiences of the Europeans, as they had been exposed to both Western and African faces. Thus the indifference of the Hadza towards average European faces could have been the result of lacking the European norm in their visual experience.[22] These results suggest that the rules for extracting attractive faces are culture-independent and innate, but the results of applying the rules depend on the environment and cultural experience.[18][23]

That the preference for the average is biological rather than cultural has been supported by studies on babies, who gaze longer at attractive faces than at unattractive ones.[24][25][26] Furthermore, Mark Stauss[27] reported that 10-month-old children respond to average faces in the same way as they respond to attractive faces, and that these infants can extract the average from simply drawn faces consisting of only 4 features. Adam Rubenstein and coworkers[28] showed that already at six months of age, children not only treat average faces the same as they treat attractive faces, but they are also able to extract the central tendency (i.e. the average) from a set of complex, naturalistic faces presented to them (i.e. not just the very simple 4-features faces used by Strauss). Thus the ability to extract the average from a set of realistic facial images operates from an early age, and is therefore almost certainly instinctive.[27][28]

Despite these findings, David Perrett and his colleagues[23] found that both men and women considered that a face averaged from a set of attractive faces was more appealing than one averaged from a wide range of women's faces. When the differences between the first face and the second face were slightly exaggerated the new face was judged, on average, to be more attractive still. The three faces are difficult to distinguish one from the other, although close examination shows that the so-called "exaggerated face" looks slightly younger than the average face (composed of women's faces aged 22–46 years). Since the same results were obtained using Japanese subjects and viewers, these findings are probably culture-independent, indicating that people generally find youthful average faces[29] sexually the most attractive.[23]

Potential evolutionary explanations

Koinophilia is an evolutionary hypothesis which proposes that mate-seeking animals preferentially chose individuals with a minimum of unusual features. Koinophilia intends to explain the clustering of organisms into species and other issues described by Darwins Dilemma.[22][30][31][32] The koinophilia hypothesis predicts that sexual creatures should avoid individuals with unusual and mutant features, both physical and behavioural – explaining why what humans determine to be a beautiful face contains no extreme features. This is advantageous because most mutations that manifest themselves as changes in appearance, functionality or behavior, are disadvantageous.[30][33]

An alternative candidate, like-attracts-like, is not a workable explanation, as it would result in assortative mating rather than the observed averageness.[1][2]

See also

References

  1. ↑ 1.0 1.1 1.2 Ayala, F.J. (1982) Population and Evolutionary Genetics p. 60. Menlo Park, California: Benjamin/Cummings. ISBN 0-8053-0315-4
  2. ↑ 2.0 2.1 2.2 Buss, D.M. (1985) Human mate selection. American Scientist 37, 47-51
  3. ↑ Galton, F. (1878). Composite portraits, made by combining those of many different persons in a single resultant figure. J. Anthropol. Inst. 8, 132–144.
  4. ↑ Francis Galton. Inquiries in Human Faculty and its Development. Retrieved April 20, 2015.
  5. ↑ Rhodes, Gillian; Zebrowitz, Leslie, A. (2002). Facial Attractiveness - Evolutionary, Cognitive, and Social Perspectives. Ablex. ISBN 1-56750-636-4.
  6. ↑ Fiona Macrae (27 December 2009). "Skin deep: Beautiful faces have Miss Average proportions". Daily Mail. Retrieved 2011-07-31. All were head shots of the same person with different distances from eyes to mouth or between the eyes. She was at her most attractive when the space between her pupils was just under half, or 46 per cent, of the width of her face from ear to ear. The other perfect dimension was when the distance between her eyes and mouth was just over a third, or 36 per cent, of the overall length of her face from hairline to chin. ... Celebrities whose faces are in perfect proportion include Jessica Alba, Liz Hurley and Shania Twain... Professor Kang Lee, of the University of Toronto, said: "...Our study proves that the structure of faces also contributes to our perception of facial attractiveness."
  7. ↑ 7.0 7.1 Langlois, J.H. & Roggman, L. (1990). Attractive faces are only average. Psychol. Sci. 1, 115-121.
  8. ↑ Langlois, J.H., Roggman, L.A., Musselman, L., Acton, S. (1991). A picture is worth a thousand words: Reply to "On the difficulty of averaging faces." Psychological Science 2, 354-357.
  9. ↑ Langlois, J.H., Roggman, L.A., Musselman, L. (1994). What is average and what is not average about attractive faces? Psychological Science 5, 214-220
  10. ↑ Langlois, J.H., Musselman, L. (1995). The myths and mysteries of beauty. In D.R. Calhoun (Ed.), 1996 Yearbook of Science and the Future , pp. 40-61. Chicago: Encyclopædia Britannica, Inc.
  11. ↑ Kalick, S.M., Zebrowitz, L.A., Langlois, J.H., Johnson, R.M. (1998). Does human facial attractiveness honestly advertise health? Longitudinal data on an evolutionary question. Psychological Science,9, 8-13
  12. ↑ Rubenstein, A.J., Langlois, J.H., Roggman, L.A. (2002). What makes a face attractive and why: The role of averageness in defining facial beauty. In G. Rhodes & L.A. Zebrowitz (Eds.), Facial attractiveness: Evolutionary, cognitive, and social perspectives: Westport, CT: Ablex
  13. ↑ Hoss, R.A., Langlois, J.H. (2003). Infants prefer attractive faces. In O. Pascalis & A. Slater (Eds.), The development of face processing in infancy and early childhood: Current perspectives pp. 27-38. New York: Nova Science Publishers.
  14. ↑ Rhodes, G., Tremewan, T. (1997) Averageness, exaggeration, and facial attractiveness. Psychol. Sci. 7, 105–110.
  15. ↑ Valentine, T., Darling, S., Donnelly, M. (2004). Why are average faces attractive? The effect of view and averageness on the attractiveness of the attractiveness of female faces. Psychon. Bull. Rev. 11, 482–487
  16. ↑ average faces are consistently more attractive than the faces used to generate them
  17. ↑ 17.0 17.1 Rubenstein, A.J., Langlois, J.H., Roggman, L.A. (2002). What makes a face attractive and why: The role of averageness in defining facial beauty. In G. Rhodes & L.A. Zebrowitz (Eds.), Facial attractiveness: Evolutionary, cognitive, and social perspectives: Westport, CT: Ablex.
  18. ↑ 18.0 18.1 18.2 Grammer, K., Fink, B., Moller, A.P., Thornhill, R. (2003). "Darwinian aesthetics: sexual selection and the biology of beauty." Biol. Rev. Camb. Philos. Soc. 78, 385–407.
  19. ↑ Rhodes, G. (2006) "The evolutionary psychology of facial beauty." Annu. Rev. Psychol. 57, 199–226.
  20. ↑ model's facial configuration is very similar to the composite's facial configuration
  21. ↑ 21.0 21.1 Apicella, C.L., Little, A.C., Marlowe, F.W. (2007). "Facial averageness and attractiveness in an isolated population of hunter-gatherers." Perception 36, 1813–1820.
  22. ↑ 22.0 22.1 Unnikrishnan, M.K. (2009). "How is the individuality of a face recognized?". Journal of Theoretical Biology 261 (3): 469–474. doi:10.1016/j.jtbi.2009.08.011.
  23. ↑ 23.0 23.1 23.2 Perrett, D.I., May, K.A., Yoshikawa, S. (1994). "Facial shape and judgements of female attractiveness." Nature (Lond.) 368, 239–242.
  24. ↑ Langlois, J.H., Ritter, J.M., Roggman, L.A., Vaughn, L.S. (1991). "Facial diversity and infant preferences for attractive faces." Dev. Psychol. 27, 79–84.
  25. ↑ Slater, A.M., Von Der Schulenburg, C., Brown, E., et al. (1998). "Newborn infants prefer attractive faces." Infant Behav. Dev. 21, 345–354.
  26. ↑ Kramer, S., Zebrowitz, L.A., San Giovanni, J.P., Sherak, B. (1995). "Infants' preferences for attractiveness and babyfaceness." In Bardy, B.G., Bootsma, R.J., Guiard, Y. (Eds.) Studies in perception and action III. pp. 389–392. Hillsdale, N.J.: Erlbaum Associates.
  27. ↑ 27.0 27.1 Strauss, M.S. (1979). "Abstraction of prototypical information by adults and 10-month-old infants." J. Exp. Psychol.: Human Learn. Mem. 5, 618–632.
  28. ↑ 28.0 28.1 Rubenstein, A.J, Kalakanis, L., Langlois, J.H. (1999). Infant preferences for attractive faces: a cognitive explanation. Dev. Psychol. 35, 848–855.
  29. ↑ Rhodes, G., Hickford, C., Jeffery, L. (2000). Sex-typicality and attractiveness: Are supermale and superfemale faces super-attractive? Brit. J. Psychol. 91, 125–140.
  30. ↑ 30.0 30.1 Koeslag, J.H. (1990). "Koinophilia groups sexual creatures into species, promotes stasis, and stabilizes social behaviour." J. theor. Biol. 144, 15–35
  31. ↑ Miller, W.B. (2013). "What is the big deal about evolutionary gaps?". In: The Microcosm within: Evolution and Extinction in the Hologenome. Boca Raton, Florida.: Universal Publishers. pp. 177, 395–396. ISBN 1-61233-2773.
  32. ↑ Unnikrishnan, M.K. (2012). "Koinophilia revisited: the evolutionary link between mate selection and face recognition.". Current Science 102 (4): 563–570.
  33. ↑ Symons, D. (1979) The Evolution of Human Sexuality. Oxford: Oxford University Press.

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