Neanderthals had a characteristic "bun head" shaped skull which allowed for expanded visual processing in the back of the brain. That left them less head space for the frontal lobe, which governs social cognition.
The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.
If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.
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