Sep 11, 2023 04:57 PM
(This post was last modified: Sep 11, 2023 04:57 PM by C C.)
https://www.wsj.com/science/human-brains..._permalink
EXCERPTS: . . . The researchers suggested that perhaps our need to maintain a large brain—to keep track of information about food, social relationships, predators and our environment—has also relaxed in the past few millennia because we could store information externally in other members of our social circles, towns and groups.
“We’re so social that we don’t have to know everything anymore,” DeSilva said. “And we collectively then operate as a pretty functional society.”
That trend is likely bolstered by our use of books, personal devices and the internet as similar information sinks, according to Chris Stringer, a paleoanthropologist with the Natural History Museum in London and Christof Koch, a neuroscientist at the Allen Institute, a Seattle-based bioscience research nonprofit. Neither were involved in the recent research.
“Our brains don’t have to work as hard,” Stringer said.
DeSilva’s group calculated that human brains had remained roughly the same size in average volume, about 1,450 cubic centimeters, for roughly the past 150,000 years. That average rapidly dropped by around 10%, or up to 150 cubic centimeters, over the course of the last few millennia.
Though average human height appears to have increased in the last few centuries, Stringer said our species had gotten noticeably shorter, lighter and smaller-boned in the past 10,000 years after the climate warmed—and brain sizes scaled down accordingly. “But that is probably not the whole story,” he added.
DeSilva’s group found that not only did the human brain size shrink in general, but also it decreased relative to our body size—suggesting that brain size reduction isn’t just a byproduct of our shrinking bodies...
[...] “We shouldn’t be too quick to say that, ‘If there was a reduction in brain size, that must have meant our ancestors 3,000 years back would have been much more intelligent,’ ” said Chittka, who wasn’t involved in the research. It is possible, Chittka and DeSilva said, that our mental circuitry evolved to be more optimized—with improved neural connections in a smaller package...
[...] Not all scientists are convinced our brains have shrunk. Brian Villmoare, a biological anthropologist at the University of Nevada, Las Vegas, co-wrote a paper last year responding to some of the work from DeSilva’s group. He said that a limited sample size—particularly of fossil skulls—may have skewed calculations with regards to brain size averages over time.
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EXCERPTS: . . . The researchers suggested that perhaps our need to maintain a large brain—to keep track of information about food, social relationships, predators and our environment—has also relaxed in the past few millennia because we could store information externally in other members of our social circles, towns and groups.
“We’re so social that we don’t have to know everything anymore,” DeSilva said. “And we collectively then operate as a pretty functional society.”
That trend is likely bolstered by our use of books, personal devices and the internet as similar information sinks, according to Chris Stringer, a paleoanthropologist with the Natural History Museum in London and Christof Koch, a neuroscientist at the Allen Institute, a Seattle-based bioscience research nonprofit. Neither were involved in the recent research.
“Our brains don’t have to work as hard,” Stringer said.
DeSilva’s group calculated that human brains had remained roughly the same size in average volume, about 1,450 cubic centimeters, for roughly the past 150,000 years. That average rapidly dropped by around 10%, or up to 150 cubic centimeters, over the course of the last few millennia.
Though average human height appears to have increased in the last few centuries, Stringer said our species had gotten noticeably shorter, lighter and smaller-boned in the past 10,000 years after the climate warmed—and brain sizes scaled down accordingly. “But that is probably not the whole story,” he added.
DeSilva’s group found that not only did the human brain size shrink in general, but also it decreased relative to our body size—suggesting that brain size reduction isn’t just a byproduct of our shrinking bodies...
[...] “We shouldn’t be too quick to say that, ‘If there was a reduction in brain size, that must have meant our ancestors 3,000 years back would have been much more intelligent,’ ” said Chittka, who wasn’t involved in the research. It is possible, Chittka and DeSilva said, that our mental circuitry evolved to be more optimized—with improved neural connections in a smaller package...
[...] Not all scientists are convinced our brains have shrunk. Brian Villmoare, a biological anthropologist at the University of Nevada, Las Vegas, co-wrote a paper last year responding to some of the work from DeSilva’s group. He said that a limited sample size—particularly of fossil skulls—may have skewed calculations with regards to brain size averages over time.
(MORE - missing details)