The shrinking human brain

[TylerDurden]

http://io9.com/5753163/our-brains-are-shrinkingand-why-this-actually-means-were-getting-smarter


The above article is, of course, very misleading as it has been recently shown that wolves, for example, are much more intelligent than dogs:-

http://www.economist.com/node/12415186

Anyway, the 1st article does point to one  interesting theory, namely  that humans have smaller brains because they have "domesticated"  themselves. The 1st article seems to have gotten it wrong re claiming that the body-size to brain ratio is the same for Cro-Magnons as for modern humans, though:-

Over millions of years, the hominid body has been shrinking but the worrying fact is that our brains are shrinking faster than our bodies -

taken from:-

http://www.ancient-origins.net/news-evolution-human-origins/scientists-are-alarmed-shrinking-human-brain-001446#sthash.i7XrfBpx.dpuf"


The last article does  have one rather convincing theory, though, :-humans lost the evolutionary pressure to be smart once they formed agricultural settlements:-

"http://www.livescience.com/24713-humans-losing-intelligence.html


imo, this explains the "Great Filter" theory as to why no sentient alien civilisations exist. In other words, they stop evolving once civilisation sets in,  and  more and more people are able to survive who, in palaeo times, would have died long before being able to breed, until, eventually, extinction occurs.
 Here is an article suggesting that the number of birth-defects is rising rapidly, no doubt partly due to improvements in medical technology, though some of the increase is attributed to environmental factors such as smoking, alcohol or pollution:-
http://www.dailymail.co.uk/health/article-105629/Women-urged-curb-lifestyles-birth-defects-rise.html

I admit I am somewhat biased in favour of  this new interpretation re socialisation, since, as an introvert, it always annoyed me that scientists in previous decades would constantly claim that increased social cooperation led to bigger human brains, whereas this new theory suggests the exact opposite!

[sabertooth]

Weston price noticed that children fed the food of civilization had narrower jaws and more dental issues, but there must have also been a reduction in brain size and function that didn't get as much attention.

Ive noticed there are a large number of small headed children in todays world, that were formula fed, and weaned on highly processed foods. Modern man no longer has the raw ingredients necessary to maintain such large brains, so there is an adaption occurring which is leading to the shrinking brain, in order to economize.  This shrinking brain is leading to the atrophy of higher mental functions which are no longer needed in the industrial world. 

[Iguana]

The above article is, of course, very misleading as it has been recently shown that wolves, for example, are much more intelligent than dogs:-

Yes, wild animals are a lot more intelligent than domestic ones. Intelligence is little needed to survive for domestic animals and for humans in our civilization. I’ve even noticed it recently with the totally wild cat (It seems he never lived with humans before) that is now my friend – I don’t like the word “tamed”. I bet he’s more smart in some ways than many humans!     

The last article does  have one rather convincing theory, though, :-humans lost the evolutionary pressure to be smart once they formed agricultural settlements:-

That’s absolutely logical.

imo, this explains the "Great Filter" theory as to why no sentient alien civilisations exist. In other words, they stop evolving once civilisation sets in,  and  more and more people are able to survive who, in palaeo times, would have died long before being able to breed, until, eventually, extinction occurs.

That’s a speculation of yours! In other worlds, others factors may enter into play, who knows?

I admit I am somewhat biased in favour of  this new interpretation re socialisation, since, as an introvert, it always annoyed me that scientists in previous decades would constantly claim that increased social cooperation led to bigger human brains, whereas this new theory suggests the exact opposite!

This “new” theory is absolutely logical. Are you sure it’s really new?

[JeuneKoq]

In a way this subject goes in pair with the "epigenetics and the cooked diet" issue. Lets just be happy we actually found a way to get back on tracks, so to speak. But in that case I guess we should also (re)turn to a life where we actually needed bigger brains. Being on a raw omnivore diet alone won't necessarily lead to that...

So the question is, should we go wild for the sake of bigger brains? Can we even return to wilderness?
Or should we concur with a life where bigger brains are not necessary?
And with all this talk about universal consciousness coming up, or something like that, will our brains be used for other purposes and grow to serve these "purposes"?

[Iguana]

It seems there’s now a broader spectrum of intelligence within humans, some people being extremely clever while others are absolutely stupid. Even if the average is plummeting, it’s probably not the case for everyone, the ones using their brain a lot keeping it in good shape, just like athletes keep their musculature in great shape.

Wild animals must probably all fall within a narrower range of intelligence within a species, like they all maintain an almost identical, ideal physical shape and are barely distinguishable from another.   

[TylerDurden]

This “new” theory is absolutely logical. Are you sure it’s really new?

Well, I have not come across it ever before, whereas the social skills/Intelligence theory has been around for years.

[JeuneKoq]

that's probably true: a physician's brain must be molded/planned differently than a painter's brain after some time... Also has to do with which part of the brain is most solicited, left or right. And it probably gets more complex than that, with all the different brain sections...

[TylerDurden]

Here is a fascinating article which  points out various explanations for the shrinking human brain-size:-

https://www.pelicanbooks.com/the-domesticated-brain/preface

The article points out that domestication of animals reduces aggressiveness. This would presumably reduce testosterone-levels and testosterone leads to bigger brains, so a lower amount of testosterone would reduce brain-size. The article points out how much more intelligent wolves, with their bigger brains, are, than dogs.

The article also points out that brain-size is not a guarantee of intelligence. It points out that some people have  survived without any reduction in mental alertness etc. even after  losing part of their brains in an accident.

The article debunks the notion that the decrease in brain-size happened when we switched from a palaeo diet of meat/fruit/veg etc.  to a diet including crops. It states that arming only appeared very recently in Aboriginal Australia but that they too had experienced that same decline in brain-size c. 20,000 years ago or so.

Another explanation for decreasing brain-size is that once the Ice-Age ended, we no longer needed big bodies with large fat-reserves so when our bodies declined in size, so did our brain-size. However, the article points out that, in previous ages, human brain-size had continued to increase despite vast climatic changes.