If Modern Humans Are So Smart, Why Are Our Brains Shrinking?

[Islander]

I find this sort of stuff fascinating, so dropped this in here in case anyone else finds it equally interesting.

Here are some leading theories about the why the human brain has been getting smaller since the Stone Age.

by Kathleen McAuliffe; illustrations by Stuart Bradford From the September 2010 issue (http://discovermagazine.com/2010/sep); published online January 20, 2011
discovermagazine.com

John Hawks (http://johnhawks.net/weblog) is in the middle of explaining his research on human evolution when he drops a bombshell. Running down a list of changes that have occurred in our skeleton and skull since the Stone Age, the University of Wisconsin anthropologist nonchalantly adds, “And it’s also clear the brain has been shrinking.”
“Shrinking?” I ask. “I thought it was getting larger.” The whole ascent-of-man thing.
“That was true for 2 million years of our evolution,” Hawks says. “But there has been a reversal.”

He rattles off some dismaying numbers: Over the past 20,000 years, the average volume of the human male brain has decreased from 1,500 cubic centimeters to 1,350 cc, losing a chunk the size of a tennis ball. The female brain has shrunk by about the same proportion. “I’d call that major downsizing in an evolutionary eyeblink,” he says. “This happened in China, Europe, Africa—everywhere we look.” If our brain keeps dwindling at that rate over the next 20,000 years, it will start to approach the size of that found in Homo erectus, a relative that lived half a million years ago and had a brain volume of only 1,100 cc. Possibly owing to said shrinkage, it takes me a while to catch on. “Are you saying we’re getting dumber?” I ask.

Read the article: http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking

[mellowsong]

I also found this fascinating but admit I don't have a clue what to think about it other than it probably means something. On the other hand, I'm also not going to worry about it :)

[Reesacat]

I was shocked — I really thought the brain capacity (at least in women!) would be increasing.....

[Islander]

I think the parallel with electronics is pertinent. Our electronic devices have become increasingly powerful and efficient until now we can carry in our pocket, more computing power than ENIAC, the first computer, that filled an entire temperature-and-humidity-controlled room. Quite possibly our brains have simply become more efficient. The brain cannot become bigger, as head size is the ultimate limiting factor in childbirth (or was until the C-section became common).

[Julieanne]

Good point Islander. My immediate reaction was 'women's brains are smaller, but they are no less intelligent than men'. So maybe another case of size doesn't matter?

[mellowsong]

I think the parallel with electronics is pertinent. Our electronic devices have become increasingly powerful and efficient until now we can carry in our pocket, more computing power than ENIAC, the first computer, that filled an entire temperature-and-humidity-controlled room. Quite possibly our brains have simply become more efficient. The brain cannot become bigger, as head size is the ultimate limiting factor in childbirth (or was until the C-section became common).

Well, the residents from the Medical University of SC cannot function without their Blackberries. It doesn't matter what you say...they plug it into their Blackberry and tell you sorry, it's not in there so you must be wrong. I told one how I take my hydrocortisone and why. He plugged it in and told me that I cannot take it that way because nothing like that is in there. They are totally dependent on electronic brains and cannot think for themselves. They are automatons/robots NOT doctors. I have very very little respect for any of the residents I see using their Blackberries to make medical decisions! I'm sure if you compared their brain size to doctors 50 or 60 years ago, they'd be smaller:rolleyes:

[highlander]

Good point Islander. My immediate reaction was 'women's brains are smaller, but they are no less intelligent than men'. So maybe another case of size doesn't matter?
I've never thought that brain size mattered much. There are so many people who seem to think it trumps all. Elephants have bigger brains than we do. Is the dumbest elephant smarter than the smartest human? I'm convinced that my cats are smarter than many people I know.

[Islander]

The African Grey parrot has a bird brain but is one of the smartest creatures on earth. (I have one of the ones with lower IQ). Alex, the African Grey who was so highly trained and died just recently, was astonishing...understood the concept of zero.

[highlander]

I loved Alex.

[Islander]

For 30 years, Alex showed he could speak, count, identify objects, and express feelings. (Click the square...trying to reconstruct vB code) (aaah...success!)


sYk-wE18BTo (http://www.youtube.com/watch?v=sYk-wE18BTo)