Anthropologists are now proposing that complex interbreeding and assimilation is likely responsible for Neanderthal disappearance 40,000 years ago, not the “superiority of their human contemporaries.” Neanderthal brains simply had more capacity devoted to vision and body control, with less left over for social interactions and complex cognition.
Neanderthals lived in a large chunk of Europe and Asia between 350,000 and 40,000 years ago, but disappeared after modern humans crossed into the area. In that past, anthropologists have explained this mysterious demise by suggesting that they were less advanced than their modern human contemporaries.
In some ways, that’s true. Neanderthals never invented a written language, developed agriculture, or significantly progressed past the Stone Age. But at the same time, their brains were just as big in volume as ours are today. Now, scientists suspect a greater portion of their brain was devoted to physical achievements, leaving less ‘mental real estate’ for higher thinking.
In a study, the research team led by Eiluned Pearce reached the conclusion after comparing the skulls of 13 Neanderthals to 32 human skulls from the same area.
“The evidence for cognitive inferiority is simply not there. What we are saying is that the conventional view of Neanderthal is not true,” Dr. Poala Villa from the University of Colorado at Boulder notes.
Instead, one of the easiest differences to quantify in the brain was the size of the visual cortex, the part of the brain responsible for interpreting visual information. As it turns out, Neanderthals had much larger eyes than ancient humans. They also had significantly larger bodies, wider shoulders, and thicker bones. In primates, we know the amount of brain capacity devoted to body control is also proportionate to body size, so scientists were able to calculate how much of our ancestors’ brains were assigned to this task.
The research team ultimately found that the amount of brain volume left over for other tasks was significantly smaller for Neanderthals than H. sapiens. It’s this “divergence in mental capacity for higher cognition and social networking” that could have led to very different fates.
“Having less brain available to manage the social world has profound implications for the Neanderthals’ ability to maintain extended trading networks,” Robin Dunbar, one of the co-authors, said. They “are likely also to have resulted in less well-developed material culture—which, between them, may have left them more exposed than modern humans when facing the ecological challenges of the Ice Ages.”
Source: Smithsonian Magazine, sci-news.com