New research finds that Neanderthals' large eyes may have been their downfall.

The study was conducted by the University of Oxford and the Natural History Museum, London, and suggests that Neanderthals' highly adapted eyes may have prohibited them from keeping up with humans.

The team observed data from 27,000 fossils found in Europe and the Near East, and selected 32 human and 13 Neanderthal skulls from 75,000 years ago. At this stage in history, Homo sapiens were anatomically identical to modern humans. And a key difference in the two types of skulls may shed light on why Neanderthals died, while humans went on to populate every corner of the world.

What the team found was that the Neanderthals’ eye sockets were considerably larger than those of their darker, slimmer, hairless cousins from Africa. Bigger eye sockets also mean bigger eyes. But how could this be a bad thing?

The answer lies in brain organization.

“Since Neanderthals evolved at higher latitudes and also have bigger bodies than modern humans, more of the Neanderthal brain would have been dedicated to vision and body control, leaving less brain to deal with other functions like social networking," Eiluned Pearce, the lead author of the study, told Indian Express. Pearce works at the Institute of Cognition and Evolutionary Anthropology at the University of Oxford.

Not that Neanderthals had small brains. In fact, fossil evidence shows that our hairy European cousins actually had larger brains than we do. But more of that larger brain was devoted to seeing at higher, darker latitudes, diverting brain energy from social networking (the old school, non-Twitter kind).

“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,” Pearce said.

Other research at Oxford finds that even humans living in Europe developed larger vision areas to account for the lower light in the region.

“Overall,” Pearce said, “differences in brain organisation and social cognition may go a long way towards explaining why Neanderthals went extinct whereas modern humans survived,”