Modern humans possess brain structures larger than their Neanderthal counterparts, suggesting we are distinguished from them by different mental capacities. We are currently the only extant human lineage, but Neanderthals, our closest-known evolutionary relatives, still walked the Earth as recently as 24,000 years ago.
     To find out more, researchers used CT scanners to map the interiors of five Neanderthal skulls as well as four fossil and 75 contemporary human skulls to determine the shapes of their brains in three dimensions. The investigators discovered modern humans possess larger olfactory bulbs at the base of their brains. This area is linked primarily with smell, but also with other key mental functions such as memory and learning. Intriguingly, smell may also play a social role, such as for recognising family and friends and reinforcing group cohesion.
     Compared with Neanderthals, modern humans also possess larger temporal lobes, an area near the base of the brain. "Neuroscientists relate temporal lobes with language functions, long-term memory, theory of mind (the ability to consider the perspective of others), and also emotions," says Markus Bastir, a paleo-anthropologist at Spain's National Museum of Natural Sciences, in Madrid. We also have a relatively wider orbito-frontal cortex than Neanderthals, a part of the brain immediately above the eyes. The area is linked with decision-making.
     All in all, it remains unclear exactly how these brain differences might have set us apart from Neanderthals, Bastir cautioned. We only know how these skulls moulded themselves around these brains, and not the precise structures of the brains in question.

Edited from LiveScience (13 December 2011), ScienceDaily (14 December 2011)