Did large eyes cause the demise of the Neanderthal?

A study of Neanderthal skulls has led scientists to suggest that the size of their eyes may have led to their demise and eventual extinction. Larger eyes meant that more of their brain was dedicated to seeing in the longer darker nights in Europe and the generally lower light conditions compared to Africa. Modern humans who stayed in Africa for longer (thus in better light) did not evolve this eye and brain adaptation and so their brains could develop higher level thinking, which enabled them to better adapt to the ice ages through improved clothing (for example evidence of needles and early tailoring has been found while Neanderthal clothing remained cruder) and to develop larger social groups.

However modern humans living at higher altitudes have also evolved larger vision processing areas in their brains and this has not resulted in reduced cognitive abilities. The findings seem to run counter to recent research that has dispelled the earlier view that Neanderthals were "stupid brutes" and instead were only slightly less intelligent than ourselves. Indeed although modern humans' advantage was only slight it was apparently just enough to tip the balance in their favour in the battle for survival during the ice ages.

John Hawks is among those sceptical.

The single most important correlate of orbit diameter is body mass. Neandertals were bigger on average. QED.
— John Hawks (@johnhawks) March 13, 2013