Chance, not natural selection, best explains why the modern human skull looks so different from that of its Neanderthal relative, according to a new study led by Tim Weaver, assistant professor of anthropology at UC Davis.
. . .
Weaver and his colleagues compared cranial measurements of 2,524 modern human skulls and 20 Neanderthal specimens, then contrasted those results with genetic information from a separate sample of 1,056 modern humans.
The scientists concluded that Neanderthals did not develop their protruding mid-faces as an adaptation to icy Pleistocene weather or the demands of using teeth as tools, and the retracted faces of modern humans are not an adaptation for language, as some anthropologists have proposed.
To be honest, I never quite liked a lot of the ideas put forth on Neanderthal cranial morphology. I always figured they just looked different because they split off earlier.