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Human jaw shrinkage

Human jaw shrinkage is the phenomenon of continued size reduction of the human mandible and maxilla over the past 12,000 to 15,000 years. Modern human lifestyles and diets are vastly different now from what they were for most of human evolutionary history. Human jaws, as well as oral cavities, have been shrinking ever since the spread of agriculture during the Neolithic Revolution (c. 12,000 years ago). This has been confirmed by bone remains dated to this time period.[1][2] Researchers are able to infer the basic lifestyle practices of past cultures, enabling them to link jaw size with lifestyle behaviors. Bones from burial sites of past hunter-gatherer societies are associated with larger jaws and mouths, while bones retrieved from former farming cultures have decreased jaw size.[1][3][4]

Bones from farming societies indicate the presence of dental malocclusions, commonly known as non-straight teeth.[1] Within recent centuries, as food has become more processed and soft in form, a rapid increase in non-straight teeth, smaller jaws, and mouths has been observed, as well as decreased space for wisdom teeth, and associated health conditions. Such conditions include sleep apnea, constricted airways, and decreased respiratory fitness.[2][5][4][6] Medical professionals have been making similar observations and documenting them for hundreds of years.[4] Changes in diet, lifestyle, and breathing patterns have led to maladaptive phenotypic expression in terms of morphological craniofacial development that starts in childhood but persists throughout the lifespan.[4]

  1. ^ a b c Pinhasi, R., Eshed, V., & von Cramon-Taubadel, N. (2015). Incongruity between affinity patterns based on mandibular and lower dental dimensions following the transition to agriculture in the Near East, Anatolia, and Europe. PLOS ONE, 10(2), e0117301.
  2. ^ a b Lieberman, D. E., Krovitz, G. E., Yates, F. W., Devlin, M., & Claire, M. S. (2004). Effects of food processing on masticatory strain and craniofacial growth in a retrognathic face. Journal of human evolution, 46(6), 655-677.
  3. ^ Cite error: The named reference :4 was invoked but never defined (see the help page).
  4. ^ a b c d Kahn, S., Ehrlich, P., Feldman, M., Sapolsky, R., & Wong, S. (2020). The jaw epidemic: Recognition, origins, cures, and prevention. BioScience, 70(9), 759-771.
  5. ^ Ehrlich, P. R., & Blumstein, D. T. (2018). The great mismatch. BioScience, 68(11), 844-846.
  6. ^ Cite error: The named reference :10 was invoked but never defined (see the help page).

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