November 27, 2012 | David F. Coppedge

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.


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  • Robert Byers says:

    The great presumption behind all this is that bigger brains equals bigger smarts.
    Really? Are they measuring kids today!

    In this age where small is brilliant like in computers it demands evidence that intelligence is related to brain size.
    Our bigger brains is just for other reasons.
    Remember we think in a spiritual world and not a physical one.
    Just like God.
    Evolutionists should first be forced to prove brain size is related to intelligence.
    First things first.

  • rockyway says:

    1. “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…”

    – This isn’t the way it happened of course. What happened was that after humans got big brains (this may or may not have been the result of falling out of trees) they realized that they would now have to exercise more to feed these big brains. This led to the evolution of the treadmill and the exercise bike; which allow one to eat and excerise at the same time.
    I think this sheds considerable light upon the whole evolutionary scenario; or at least as as much as a single hamburger can produce.

    2. “Or, humanity’s cognitive capacity may be a simple side effect, a neurobiological change that sort of got “dragged along” with aerobic capacity.

    – We see here again, how textbook orthodoxy is taken to be fact rather than speculation, and one simply extrapolates from there. (Sort of like launching a rocket from a giant marshmellow.)

    3. ”…children with more physical activity have more brain volume than couch potatoes.
    – This doesn’t mean the size of the brain grows. There’s a difference between increasing brain cells or connections, and growth in cranial capacity.

    4. “The evolution of the human brain is probably the result of a lot of complex selection pressures interacting with each other…”

    – The evolution of the human brain (in size and intelligence) is one of the big Darwinian myths; and one with nothing in empirical (observational) science to back it up. The whole idea is a reconstruction of an imagined history, that is supposed to be based on a small handful of widely scattered bone fragments, but is really formed out of the dust of metaphysical speculation. (This isn’t a provable claim any more than the idea that Mickey Mouse evolved from the common barn mouse is.)

  • AnthonyMills says:

    Inner ear development indicates fitness because the underlying causes of fitness tend to be the underlying causes of inner ear development, and it’s just hard to be fit without decent balance. Thus the two tend to happen together.

    It’s fairly well established that being fit and active maximizes your brain’s effectiveness; that’s why chess grandmasters focus on being in good shape as well as studying chess. Being fit removes roadblocks; since your brain takes so much of your body’s energy budget, making your body better at delivering energy helps your brain out, making some things possible that weren’t before.

    What the hypothesis says is, perhaps with better fitness, early humans had more energy to spend. Some spent it on brains, and some spent it on muscles, and in those particular circumstances, it turned out to be more efficient to spend the extra energy on extra brainpower.

    We can agree on one thing, though; it’s doubtful it was the “key”. But it’s an intriguing hypothesis to add to the list of causes nonetheless.

    • Editor says:

      Anthony, the hypothesis in the story has nothing to do with current humans playing chess. It has to do with an unguided process leading from apes to philosophy. Read the article and commentary again. All you have said so far (“perhaps…intriguing…”) is that you can imagine this notion is not as dumb as it sounds. Beware the siren song of the storytellers.

  • lux113 says:

    Anthony, with all due respect, your answer is well worded and, from what I can tell, grammatically free of error – it even includes a semi-colon. I find it amazing that you can say something which seems intelligent but misses the obvious.

    If a person is sick (unhealthy) they will have more trouble doing almost anything – including thinking. So yes, if you are healthy it’s ‘good for your brain’.

    But that by no means implies any sort of connection between being healthy/exercising regularly and being intelligent.

    Quite the contrary we have a world chock full of very obese and lethargic people who are brilliant – and also a whole variety of health nuts who are not exactly Einsteins.

    There is no correlation at all. None.

    But yes, if the obese lethargic guy trims down a bit and eats his Wheaties in the morning – it’s possible he might think a bit clearer.. because a working clock functions better than a broken one. The fact that his brain will work better if his body works better doesn’t connect health to intelligence though… it connects health to .. well, health.

    Their theory is not “intriguing”, it’s juvenile, and unbelievably poorly conceived. It disappoints me Anthony that you can appear to think so clearly.. yet miss the obvious. Possibly you should work out more.

    Not trying to be mean.. but it just offends me anyone could find this sad excuse for science “intriguing”.

  • lux113 says:

    And Anthony..

    In this line you wrote: ” early humans had more energy to spend. Some spent it on brains, and some spent it on muscles”

    Something smacks of Lamarck — not only the visage of them storing up their energy to invest in either brains or muscle – but more importantly that you make it sound as if they had a choice.

    We do not “invest” in the process of evolution, we are not storing away bits of energy to devote to a heretofore never attempted genetic mutation. This entire concept that evolutionists throw around of having extra energy to produce new changes in our make up is a dead end alley. It’s neat as a philosophical / conceptual idea – but ridiculous in it’s actual implementation. If you have energy, your body will use that energy – to maintain the structures it has – but there is no secret reservoir for “extra” energy to be stored and then used once your progeny are about to be born to produce a new appendage or bigger brain.

    Seriously, I’ve heard it stated how cooking food over flame caused it to produce a much higher level of energy and that led us to a faster rate of evolution. Though I’m sure it’s true that cooked food provides more energy – that extra energy cannot be logically put to any evolutionary use – it would just mean you have… more energy. You could hunt longer.. sleep less. Maybe that would mean you have more muscles – or more time to learn – but that energy would be spent on the structures already in place and wouldn’t fundamentally change your offspring.. other than to say that if you were healthier I’d anticipate the child would be healthier as well.

    The vehicle for evolution as the theory stands is genetic mutation. Would more energy produce more mutations? If so, why? All we are talking about is energy.. basically like gas in the car – a good supply of it keeps the mechanism running.. but how do we go from that to using the energy to produce a novel improvement to the car? What would energy even have to do with it?

    I guess what I’m saying is that energy is like a B vitamin… you need 100% of your daily dose – but having 50 million % isn’t going to make you any better off.

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