Tooth Size Reduction: A Hominid Trend

C. L. Brace proposes that the reduction in the size of the anterior teeth in hominid phytogeny resulted from the accumulation of random mutations when these teeth became selectively neutral as a result of increased tool use. In contrast, we contend that the incisors have adaptive significance; they reflect the selection pressures on the whole functional matrix in which they exist. Moreover, the accumulation of mutations is not biologically possible without affecting the fitness of the whole organism. Lastly, there is no apparent relationship between the size of the anterior teeth and the level of technology in contemporary populations, as the Brace model would predict.