Humans Got Big Brains By Exercise
Someone didn’t think this one through.
“Human brawn may be the key to why human brains are so big, according to a new hypothesis linking exercise to the evolution of our oversize noggins,” begins an article on Live Science by Stephanie Pappas, “Did Exercise Make the Human Brain So Buff?”
The article presents the speculations of a team led by David Raichlen, an anthropologist at the University of Arizona. “The idea has yet to be thoroughly tested,” Pappas cautioned, but it goes like this:
Now, Raichlen and his colleagues have a new idea to add to the mix: Perhaps human brains didn’t just grow because our species was facing more mental challenges. Maybe, instead, the shift to an increasingly aerobic hunter-gatherer lifestyle about 1.8 million years ago boosted our species’ athletic prowess. Because of links between exercise and the brain, this natural selection for faster, more agile humans might have resulted in smarter, bigger brains.
The bigger brains may have been a crucial piece of this puzzle, given that more cognitive ability would allow one to hunt and gather farther afield than those who came before, Raichlen said. Or, humanity’s cognitive capacity may be a simple side effect, a neurobiological change that sort of got “dragged along” with aerobic capacity.
From here, Pappas went on to describe experiments with mice that showed they were smarter if they got more exercise. Elderly people who remain active suffer less atrophy in their brains, while children with more physical activity have more brain volume than couch potatoes. “Thus, natural selection for fitness in human ancestors could have triggered an increase in actual brain juice, prompting growth and development.”
The authors did admit a few problems with this idea. “Unfortunately, Raichlen and his colleagues wrote, little is known about the aerobic fitness of humans’ closest ancestors, given that they’re not around to jump on a treadmill today.” For primates and fossil hominids, there are only inferences from inner ear development and hind limb length to use as proxies for aerobic activity.
In the final sentences of the article, Pappas lets the researchers hedge their bets:
None of this evidence proves the hypothesis, Raichlen warned. More work, particularly selective-breeding studies on animals, is needed. Nor do the researchers think exercise explains the entirety of Homo sapiens‘ evolution in brain growth.
“The evolution of the human brain is probably the result of a lot of complex selection pressures interacting with each other,” Raichlen said. “I don’t think we’re going to find just one pressure that drove all of human brain evolution.“
Apparently the research team wrote in a Royal Society journal that the idea is “worth a deeper look.”
OK, let’s give it a deeper look. It won’t take long, because their hypothesis is so shallow.
If this notion were correct, cheetahs, not humans, would be writing philosophy books. Usain Bolt, not Stephen Hawking, would be solving cosmology equations in his head. There are so many flaws in this simplistic generality that it’s hard to know where to start. Does brain size alone mean intelligence? Then whales win. How can inner ear development indicate fitness? If hunting and gathering far afield means smarts, why aren’t grizzly bears and lions the smartest animals on earth? Why do their prey often outsmart them or outrun them?
Three criticisms are even worse, as if the hypothesis needs the overkill. (1) Circular reasoning: they assumed natural selection only to use it as the explanation. (2) They themselves provided the grounds for disbelieving their hypothesis, by admitting that there “complex selection pressures” involved. This is the problem with composite explanations in science. Which factor is the critical one, and by how much? If you can’t establish that aerobic fitness was crucial for intelligence, you’ve contributed no explanation at all. Notice how many escape words they employed: may, could, might, etc. (3) The hypothesis is self-refuting. If intelligence just got “dragged along” as a side effect when hominids went on a fitness program, these researchers have no grounds for trusting their own reasoning, including the reasoning that natural selection produced bigger brains.
This is how you need to critique these evolutionary claims. It’s deplorable that such silliness gets dished out by Lie Seance and all the other monolithically-Darwinian secular “science” sites. Why doesn’t Stephanie Pappas use her own head and ask these kinds of obvious questions? Why doesn’t she quote anyone who can give scientific reasons why the brain is designed? The answer is simple: if she did, the Darwin Politburo would see to it she got expelled pronto lest she help people think clearly.