ネアンデルタール人消滅の謎を解くヒントは脳にある

The structure of Neanderthals’ brains may have affected their social and cognitive abilities and contributed to their replacement by Homo sapiens, according to a study in Scientific Reports.

Naomichi Ogihara, Hiroki Tanabe and colleagues used virtual casts of four Neanderthal and four early Homo sapiens skull fossils to reconstruct the size of their brains. The authors then used MRI data from the brains of 1,185 participants to model the average human brain. This computer model was then deformed to match the shape of the skull casts, which allowed the researchers to predict what the brains of early Homo sapiens and Neanderthals may have looked like and how individual brain regions may have differed between the two species.

The authors found that while early Homo sapiens did not have larger brains than Neanderthals, they had significantly different brain morphologies, including a larger cerebellum. Using existing data from 1,095 participants, the authors examined the relationship between the size of the cerebellum and abilities such as language comprehension and production, working memory and cognitive flexibility. Their findings suggest that the differences in the early Homo sapiens’ brains meant they may have possessed better cognitive and social abilities than Neanderthals. This may have affected early humans’ ability to adapt to changing environments, increasing their chances of survival compared with the Neanderthals.