alexjrgreen wrote:
Weaker muscles and a lighter skeleton allowed modern humans to...
...survive famines and swim.
The Neanderthals survived many famines, and since they hunted seal and porpoise off Gibraltar they must have been able to swim. Possibly not as good at running, though.
They didn't get through that last famine too well.
As for swimming, fine, I really wasn't thinking about Neanderthals but lets run with it. Is a Neanderthal as heavy and muscular as a gorilla? Can a gorilla swim? How many great apes out there can swim? I just think it's funny that everyone leaps to the intelligence factor when examining human strength. Maybe there are other reasons that we aren't as buff as gorillas.
the oxygen required by their muscles would have reduced the amount available to the brain
How do you get to this conclusion? I would not say that e.g. basketballplayers are dumber, or some very tall body builders (unless they take anabolics, maybe gggg).
So why do you get to the conclusion that more muscle mass reduces the amount of oxygen available to the brain?
If that was so then everyone doing sports would be automatically getting dumber. The oposite is true though.
Their speech abilities might have been more limited though. I know for sure that their elbows did not allow them to throw spears.
The oxygen absorbed by the lungs goes to the gut, the muscles and the brain. The 'fight or flight' reaction shuts down the operation of the gut to free up oxygen for the muscles.
Training for sport increases lung capacity and improves muscle efficiency, which raises the amount of oxygen available to the brain when the body is at rest. You need to be reasonably fit to think clearly while you're running.
increases lung capacity and improves muscle efficiency
Exactly, which is why I think that higher muscle mass does not mean less brain power.
Bigger muscles require more nerves to control them, which adds brain mass but not IQ. Whales have much bigger brains than we do, but they're mostly taken up controlling their enormous bodies.
The oxygen from the lungs is limited. Big muscles, however efficient, still use lots of oxygen. Which means there's less to go round...
increases lung capacity and improves muscle efficiency
Exactly, which is why I think that higher muscle mass does not mean less brain power.
Bigger muscles require more nerves to control them, which adds brain mass but not IQ. Whales have much bigger brains than we do, but they're mostly taken up controlling their enormous bodies.
The oxygen from the lungs is limited. Big muscles, however efficient, still use lots of oxygen. Which means there's less to go round...
That's not actual true. Big muscles use the same amount of nerves to control as small muscles. Whales have huge brains because they have all of our senses plus another one. Sonor takes a huge amount of processing to work.
What is the difference between ignorance and apathy? I don't know and I don't care.
So it all boils down to... they had bigger brains and that's correlated with mental capacity.
Yes, we've seen this correlation to some degree between animals, and we've even seen it a little bit between humans. But between humans, the correlation is really weak, and there are definately animals that defy the logic. The cranial size evidence is crap.
Neanderthals Were Too Smart to Survive wrote:One of the most important means by which innovations are preserved and transmitted is language. Neanderthals had language themselves. This was proven in 1983 when a Neanderthal hyoid bone was found at the Kebara Cave in Israel. The hyoid is a small bone that holds the root of the tongue in place, a requirement to human speech and, therefore, its presence seems to imply some ability to speak.
Proven that they had language? What? Because they had the physical ability? Yeah right, that's also a crap statement. This site is horrible.
Look, I'm already familiar with that stuff. It leads to fun speculation. I was wondering if anyone had any real evidence.
*edit: conjecture is interesting if supported well enough. If you can point me to some peer-reviewed academic articles on the subject, I'd love to take a look at them.
Last edited by MirariNefas on Fri Oct 16, 2009 12:23 am, edited 2 times in total.
pfrit wrote:Whales have huge brains because they have all of our senses plus another one. Sonor takes a huge amount of processing to work.
There's a bit more than that, the brain does more than just think. Anything in the autonomic nervous system also has to increase in size with the size of the animal, and anything with biochemical significance. Bigger tissues means you need bigger glands to produce hormones for those tissues, that sort of thing. I'll go out on a limb and say that glands probably increase in size more than proportionately; a tissue twice as big needs twice as much hormone, but the hormone also has to travel farther, and has to perfuse deeper into a tissue away from blood vessels, so the animal probably needs an even higher hormone concentration to get twice as much into that tissue. I could be wrong, maybe it just has a higher blood pressure and faster blood flow, but still, an animal twice as big will at least have glands twice as big.
Given that the overall brain size of an organism increases in size less than proportionately with body size (a scale of 0.75, from wikipedia), the percentage of brain mass devoted to just maintaining bodily homeostasis will increase. So a whale has a bigger brain because it has a really big pituitary gland, and so on.
pfrit wrote:Whales have huge brains because they have all of our senses plus another one. Sonor takes a huge amount of processing to work.
There's a bit more than that, the brain does more than just think. Anything in the autonomic nervous system also has to increase in size with the size of the animal, and anything with biochemical significance. Bigger tissues means you need bigger glands to produce hormones for those tissues, that sort of thing. I'll go out on a limb and say that glands probably increase in size more than proportionately; a tissue twice as big needs twice as much hormone, but the hormone also has to travel farther, and has to perfuse deeper into a tissue away from blood vessels, so the animal probably needs an even higher hormone concentration to get twice as much into that tissue. I could be wrong, maybe it just has a higher blood pressure and faster blood flow, but still, an animal twice as big will at least have glands twice as big.
Given that the overall brain size of an organism increases in size less than proportionately with body size (a scale of 0.75, from wikipedia), the percentage of brain mass devoted to just maintaining bodily homeostasis will increase. So a whale has a bigger brain because it has a really big pituitary gland, and so on.
When I say whales have huge brains, I mean that their brains are larger than a humans in proportion to body size. Cetaceans do have proportionaly larger brains than humans.
What is the difference between ignorance and apathy? I don't know and I don't care.
Well that nixes the 0.75 thing, but doesn't really change my point. It's not all just given to greater sensory processing, though I'm sure that's a significant (and maybe dominant) factor. What I mean is, if the proportion of information processing is kept the same, I'd still expect a greater proportional brain size.
I concede that this doesn't work as well for dolphins.
pfrit wrote: When I say whales have huge brains, I mean that their brains are larger than a humans in proportion to body size. Cetaceans do have proportionaly larger brains than humans.
I think you dropped a work. You meant to say that cetaceans do NOT have larger brains in proportion to humans.
KitemanSA wrote:Indeed, of those listed, only mice do, which seems to really destroy the mass ratio argument. Of course, maybe they are smarter than us.
Well, they were the ones to commission Slartibartfast to build the Earth after all.
While mass of grey-matter is almost sure to play a role in relative intelligence levels, I'm of the opinion that it is quite a bit more complicated than that.
