Published online by Cambridge University Press: 02 October 2003
A premise of Corballis's theory is that speech arose when vocalization co-opted existing gestural functions in the left ventral premotor cortex. Yet, visuomotor functions in this region remain largely unchanged between humans and macaques and have no discernible connection to gestural communication. This functional continuity suggests that language production is not the result of modifying existing motor functions in this region.