I was hoping to have a more in depth post on this for the upcoming edition of the Four Stone Hearth but I am not going to get it finished in time. Here is the short version.
The difference between the developmental patterns of modern humans and Neanderthals is most prominent directly after birth, when the shape of the vault is extremely sensitive to the tempo and mode of brain growth … When the cranial bones are thin and not yet fully ossified, the shape changes of the frontal and parietal bone are largely driven by the increase in brain volume. While the growth of the face affects the shape of the cranial base …, it is unlikely that this alone could explain the shape changes of the parietal and occipital bone shown in Figure 1. We suggest, therefore, that species differences in brain growth rates … and timing underlie the uniquely modern human globularization phase.
During dental ages 2-6, according to Gunz et al endocranial shape changes are similar in chimps, humans, and Neanderthals. In the PNAS paper (linked to above) it was argued that two distinct developmental trajectories are identified with the modern human trajectory being more derived than the Neanderthal and the Current Biology paper links this, briefly, to Green et al paper “A draft sequence of the Neandertal genome.” – which identified some genes having to do with cognition that are derived in modern humans.
At some point I will have more to say on this. In the meantime, check out the Current Biology paper. Also, if you haven’t already please submit any interesting anthropology posts you come across to either myself or Duane at Abnormal Interests.