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

[Ichingcarpenter]

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

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


John Hawks 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.

Big Snip:


Which brings us to an unpleasant possibility. “You may not want to hear this,” says cognitive scientist David Geary of the University of Missouri, “but I think the best explanation for the decline in our brain size is the idiocracy theory.” Geary is referring to the eponymous 2006 film by Mike Judge about an ordinary guy who becomes involved in a hibernation experiment at the dawn of the 21st century. When he wakes up 500 years later, he is easily the smartest person on the dumbed-down planet. “I think something a little bit like that happened to us,” Geary says. In other words, idiocracy is where we are now.


Link:
http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking/article_view?b_start%3Aint=0&-C=


I found it an amusing article ..... its about three pages long with a lot of conflicting reasons.

[MarkCharles]

1. Interesting and distressing theory, born out by evidence

most of said evidence can be seen in Republicans. We see a rapid decline in brain size when comparing Eisenhower to Bachmann and to GWBush and to Perry!

[kickysnana]

2. Monsanto and Chinese crap, really. n/t

[Ichingcarpenter]

3. A diet rich in vitamins and fish may protect the brain from brain shrinkage

Elderly people with high blood levels of vitamins and omega 3 fatty acids had less brain shrinkage and better mental performance, a Neurology study found.

Trans fats found in fast foods were linked to lower scores in tests and more shrinkage typical of Alzheimer's.


http://www.bbc.co.uk/news/health-16344228

[krispos42]

5. ???

"A diet rich in vitamins and fish may protect the brain from Elderly people with high blood levels of vitamins and omega 3 fatty acids?"


Are these elderly people zombies?

[Ichingcarpenter]

7. LOL... changed it but the other one was definitely funnier

and more zombie like...LOL

[HopeHoops]

4. Cable television.

[krispos42]

6. "Jerry Springer"

[Warpy]

8. It probably had to be bigger due to the physical stress

of living a nomadic lifestyle, following and chasing game and needing to know where and when edible plants would ripen.

My guess is that the major shrinkage occurred with the invention of agriculture and the more sedentary lifestyle of raising and harvesting crops. Concurrently, the variety of foodstuffs decreased sharply as people only grew what gave them the biggest caloric return for calories expended in farming.

However, a gradual dumbing down also makes some sense as a devolutionary force that might keep us from blowing up the planet.

One thing should be pointed out, though: it's not the size of the brain but the number and depth of convolutions on its surface that give us the most brain power. This is why the "women have smaller brains, must be dumber" guys are all wrong.

[Ichingcarpenter]

9. The Nethanderals had larger brains but more muscle mass

but we know nothing of the convolutions, so I think the diet of hugh amounts of protein bears this out.

I did like that they had a idiocracy theory.

The GOP field bears that out too.

[Odin2005]

10. It's because modern humans are less physically robust then we were 10,000 years ago.

We have become more lightly built over the last 10,000 years.

Also, interestingly, people on the Autism spectrum are known to tend to have bigger crania than average.

[tinrobot]

11. We're outsourcing the work.

When we started cooking, we outsourced a portion of our digestion to an external heat source. As a result, our intestines shrank.

We outsource heavy lifting to machines, so we have smaller muscles than our ancestors.

Now we outsource memory and other cognitive processes to writing, printing, calculating machines, and now computers.