Neandertals famously had larger cranial capacities than modern humans, and, have gone through multiple phases of de- and re-humanization. A few weeks ago there was a revision of the idea that Neandertals in France ~30,000 years ago adopted some aspects of modern human culture through diffusion. This was a support for the Neandertal "ooga-booga" thesis. In contrast last spring we were treated to the possibility that most human beings have trace but non-trivial Neandertal ancestry. This naturally made Neandertals seem a little less primitive, since we don't like to perceive ourselves as primitive. A new article in Current Biology supports the position for the primitive Neanderal, Brain development after birth differs between Neanderthals and modern humans:
Neanderthals had brain sizes comparable to modern humans, but their brain cases were elongated and not globular as in Homo sapiens...It has, therefore, been suggested that modern humans and Neanderthals reached large brain sizes along different evolutionary pathways...Here, we assess when during development these adult differences emerge. This is critical for understanding whether differences in the pattern of brain development might underlie potential cognitive differences between these two closely related groups. Previous comparisons of Neanderthal and modern human cranial development have shown that many morphological characteristics separating these two groups are already established at the time of birth...and that the subsequent developmental patterns of the face are similar, though not identical...Here, we show that a globularization phase seen in the neurocranial development of modern humans after birth is absent from Neanderthals.
In other words there are developmental differences between Neandertals and modern humans. They're a little less circumspect in the text, "We find that the modern human pattern of brain development is derived compared to Neanderthals." The implication here is that the Neandertals exhibit the ancestral pattern, in common with chimpanzees. Below is figure 1, which summarizes their results:
(link acknowledge, Dienekes)