A British study shows that compared to the modern human brain, the brain structure of Neanderthals focussed much larger areas on vision and movement. This difference could have contributed to their extinction.

Neanderthals– brains were similar in size to those of modern humans, but their eyes were larger. Having larger brain areas related to vision and movement meant that there was less room left over to deal with the social interactions required for life in large groups.

“Smaller social groups might have made Neanderthals less able to cope with the difficulties of their harsh Eurasian environments because they would have had fewer friends to help them out in times of need,” explains lead author Eiluned Pearce from the University of Oxford. “Overall, differences in brain organisation and social cognition may go a long way towards explaining why Neanderthals went extinct whereas modern humans survived.”

The same researchers had previously shown that humans living in higher latitudes had more areas of the brain dedicated to vision in order to cope with low light levels. They offer the hypothesis that Neanderthals would have developed larger eyes because they evolved in Europe, while their contemporary humans originated from Africa.

Source:  http://www.sciencedaily.com/releases/2013/03/130319093639.htm