The article below is an analysis (in a non-human primate, the hyrax) that supports the hypothesis that consumption of cooked foods was a factor in the reduction of face size in humans during evolution. That is yet another example of culture (cooking food) driving morphological change. Journal title: Journal of Human Evolution Citatin details: Volume 46, Issue 6 , June 2004, Pages 655-677 Article title: Effects of food processing on masticatory strain and craniofacial growth in a retrognathic face Article authors: Daniel E. Lieberman, Gail E. Krovitzb, Franklin W. Yatesa, Maureen Devlina and Marisa St. Clairec http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJS-4CG0R52-2&_user=10&_handle=B-WA-A-W-AA-MsSAYZW-UUW-AAUDUWDVVY-AAUVZUYWVY-YBAEZZZWY-AA-U&_fmt=summary&_coverDate=06%2F30%2F2004&_rdoc=2&_orig=browse&_srch=%23toc%236886%232004%23999539993%23504276!&_cdi=6886&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4cbc7c1f4cd9ac18c4a1f11f0055ff32 Abstract Changes in the technology of food preparation over the last few thousand years (especially cooking, softening, and grinding) are hypothesized to have contributed to smaller facial size in humans because of less growth in response to strains generated by chewing softer, more processed food. While there is considerable comparative evidence to support this idea, most experimental tests of this hypothesis have been on non-human primates or other very prognathic mammals (rodents, swine) raised on hard versus very soft (nearly liquid) diets. Here, we examine facial growth and in vivo strains generated in response to raw/dried foods versus cooked foods in a retrognathic mammal, the rock hyrax (Procavia capensis). The results indicate that the hyrax cranium resembles the non-human primate cranium in having a steep gradient of strains from the occlusal to orbital regions, but differs from most non-anthropoids in being primarily twisted; the hyrax mandible is bent both vertically and laterally. In general, higher strains, as much as two-fold at some sites, are generated by masticating raw versus cooked food. Hyraxes raised on cooked food had significantly less growth (approximately 10%) in the ventral (inferior) and posterior portions of the face, where strains are highest, resembling many of the differences evident between humans raised on highly processed versus less processed diets. The results support the hypothesis that food processing techniques have led to decreased facial growth in the mandibular and maxillary arches in recent human populations. Tom Billings