Evolution and humans: Neanderthal brain difference (Evolution)

by David Turell @, Friday, April 27, 2018, 19:38 (59 days ago) @ David Turell

The cerebellum is different:


"The results show that although there was no difference in the overall size of Neandertals’ brains, significant differences may have characterized the dimensions of specific regions, particularly the cerebellum. “This was surprising since the cerebellum is traditionally considered important for motor-related functions, Ogihara says. “We initially expected that the frontal lobe would be different between the two species because it has been considered to be related to higher cognitive functions, but it was not the case.”

"The researchers, however, went further by analyzing correlations between brain scans and behavioral data in an existing database (from the Human Connectome Project). They found greater cerebellum volume is associated with abilities such as cognitive flexibility, attention, language processing and memory. “The paper gives the impression the cerebellum is intimately involved in a large number of higher cognitive functions, says evolutionary psychologist Robin Dunbar of the University of Oxford in England who was not involved in the work. “This isn’t strictly true—its function seems to be rather one of coordination between different brain units and cognitive processings—in effect, making sure computations are done in the right order. That role is almost certainly crucial to higher cognitive functions and allows us to do what we do,” he says. One reason for the importance of cerebellum volume, the authors suggest, is that unlike other regions it consists of a large array of identical processing units, so larger volumes logically equate to higher processing capacity.


"The findings do not conclusively prove what caused the Neandertals’ extinction but they do suggest brain differences probably contributed to their disappearance. “What we can say based on the present study is that innate differences in brain structure actually existed between the two species, possibly leading to differences in cognitive and social abilities,” Ogihara says. “Although the difference could be subtle, such a difference may become significant in terms of natural selection.”

"Dunbar has previously shown a relationship between brain size and social group size in primates, including human social networks. Those findings involved parts of the cortex, but similar effects may be at work here. “If [the cerebellum’s function was reduced in Neandertals, it confirms that their cognitive abilities weren’t quite as advanced as those of modern humans,” he says. “That of course doesn’t make them any less human, or shambling ape-men, but it does mean their social and cultural capacities—the traits that survival really hinges on, especially in tough times—wouldn’t have been quite as effective as those of modern humans, which may well explain why they went extinct and our lineage didn’t.'”

Comment: This study certainly shows a species can only think with the brain it is given, and more complexity gives more complex concepts.

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