Auditory capacities of human fossils: A new approach to the origin of speech

Abstract

The origin and evolution of human language has mainly dealt with the reconstruction of the upper respiratory tract of human fossils. After decades of controversy no clear results have arisen from these studies. We propose a new approach to this issue based on the possibility to reconstruct the sound power transmission, through the external and middle ear, in fossil specimens. The results thus obtained in the more than 500 kyr old fossils from the Sima de los Huesos site (Sierra de Atapuerca, Spain) show that these hominins had the same auditory capacities as modern humans. Specifically, they show a widened bandwidth of heightened sensitivity in the midrange frequencies compared with chimpanzees. Relying on the theory of communication as developed by Shannon, this widened bandwidth suggests a greater channel capacity characterized the Atapuerca (SH) hominins and is consistent with other recent suggestions foring an ancient origin for human speech capacity.