They say we only use something like 15% of our brains. There are hydroencephalytics who only have 15% of their craniums occupied with brain tissue, and they’re still pretty much functional (this is part of the brain plasticity stuff that’s so fashionable now. These folks show that brain maps are changeable).
This from Time magazine, a link supplied by Mrmacq earlier today:
“Not only does this make a hash out of the accepted theory that the brain could not become more sophisticated until it got bigger, it also casts doubt on what’s been known for the past 30 years as the “obstetric hypothesis” — the idea that big human brains, and the big human heads that resulted, are what’s responsible for the unusually deep, bowl-like shape of the human pelvis. There’s simply no way a baby noggin could move through the birth canal unless human females evolved the orthopedic architecture to accommodate it.
But sediba calls that sensible-sounding idea into question. Its skull may be small, but the pelvis of the female was already human-like, without the flat, flaring look of those belonging to other Australopithecene. That may have conveniently helped it manage the big heads that would come along hundreds of thousands of years later, but it did not evolve for that reason. “Parts of the [sediba] pelvis are indistinguishable from that of humans,” says Job Kibii, also of the University of Witwatersrand. “At least in this lineage, the obstetric hyothesis…is wrong.””
This was the theory of the pelvic shape versus cranial/brain size for early humans, but it was wrong, and gives credence to my theory, the point of this post. The massive human brain is just filler. The pelvis changed first. We don’t yet know why, but it did, and small-skulled babies just fell out when we started walking around upright. The big-headed babies stayed in, and so those were the ones that made it to term and survived.
The big-brain mutation only succeeded because it kept those kids in long enough to develop to term. It – we – and our big brains are one of those accidents of evolution, a match of mutation to external conditions, and it has nothing to do with intelligence. Your big, fat head you’re so proud of, all that does for you is keep you in Mom long enough to develop the ability to breathe air before you were spit out into the world!
So wrap 15% of your brain around that!