Neanderthals’ brains weren’t to blame for their demise, new study suggests
An idea given for the mysterious disappearance of Neanderthals about 40,000 years ago there is a difference in brain power compared to early modern humans (Homo sapiens), who invaded their territory in Eurasia and surpassed them. But a new study of brain variations reveals that Neanderthals and humans were much more similar than previously thought.
Neanderthal skulls are obviously shaped differently from those of early modern humans. While Neanderthals had longer, lower skulls with heavier brow ridges and larger nasal openingsmodern humans have a more globular skull with smaller facial features. The inside of the skull, called the endocranium, is also different in Neanderthals and modern humans.
Due to the anatomical differences between the skulls, many experts have assumed that Neanderthals I couldn’t speak as well as humanshad poor planning skills and limited short-term memory. But, problematically, these differences “have not been placed in the context of modern human demographic variations in brain anatomy, which are known to be substantial,” the researchers wrote.
To better understand the variations brain anatomyThe researchers compared two large MRI datasets of the brains of living people: 100 Chinese of Han ancestry and 100 Americans of European ancestry. In nearly 70% of the brain regions the researchers evaluated, they found that the volume differences between the Chinese brain group and the American brains were greater than those in the American brains. those found previously between Neanderthals and early modern humans.
“This evidence does not support the idea that Neanderthals had significantly different brains and cognitive abilities than the anatomically modern humans who existed at the time,” Schoenemann told Live Science in an email.
If the differences between modern human populations are not evolutionarily significant, as experts assume, then similar brain differences between Neanderthals and early modern humans would not be considered evolutionarily significant either, the researchers wrote.
The researchers noted that even small differences in behavior and brain size can potentially have important evolutionary consequences. One of the biggest differences between Neanderthals and H. sapiens The brain was found to be correlated with attention and inhibition, suggesting that Neanderthals may have had slightly lower executive functioning capacity. However, “the correlations between brain anatomy and cognition are very weak,” Schoenemann said, and “even if the differences in brain anatomy were correct, the implied cognitive differences would be very small.”
Since Neanderthals died out relatively quickly after the arrival of modern humans, “it is not clear that such small differences could actually have contributed significantly to their replacement,” the researchers wrote. Since human brains differ more among living populations today than those of Neanderthals and early modern human brains about 40,000 years ago, researchers do not think Neanderthals went extinct because they lacked the intelligence to adapt.
The new study “strongly emphasizes demographics and genetic flooding – perhaps due to certain types of cultural differences – and not innate differences in cognitive abilities as the most likely cause of Neanderthal replacement,” the researchers wrote. This idea – that the genes of a minority species are overwhelmed by those of the majority species – echoes recent research who modeled the the integration of H. sapiens in Neanderthal populationswhich could have led to the disappearance of the latter in barely 10,000 years.
Further research along these lines may be warranted, the researchers concluded, since they only compared the brains of Chinese and Americans.
“It is entirely possible that even greater differences exist between modern human populations, calling into question the evolutionary significance of estimated differences between Neanderthals in brain anatomy and anatomically modern contemporaries. H. sapiens,” they wrote.
Editor’s note: This story was updated at 4:36 p.m. EDT to include quotes from the study’s first author, Tom Schoenemann.
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