The further a society drifts from the truth, the more it will hate those who speak it. ... In a time of deceit, telling the truth is a revolutionary act. George Orwell

Tuesday, April 21, 2015

Human brain size is shrinking!

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From uncyclopedia.


Human brain (average 1100 to 1300cm^3) seem to have deteriorated at least in size, in the last couple of hundred thousands years.   How does that decline translate to intelligence?  Not sure but I would speculate that it probably does correlate!

As to the cause, anthropologists seem to be rather in agreement that nutrition may have had something to do with that.  Humankind seemed to have regressed from very healthy nomadic lifestyle based on hunting and fishing to a settled one based on farming and consuming starchy plant based food.  Which correlated with the deterioration of physical health, body size and brain size.  [add refs later]

According to this research.  Neanderthal did not have to use fire to cook their exclusively animal based meals.  My thought is that they must also have consumed plenty of DHA from animal brains and spinal cords, together with all the fats to grow and feed their very large brains of average volume 1600 cm^3 (some sources give bigger estimates) .   Ability to use fire gave Cro-Magnon (average brain volume 1500 or 1600 cm^3) an advantage when game became scarce and food versatility became useful, by the end of the last ice age.
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6 comments :

john said...

I've seen so many pro seafood arguments regarding brain size; however, from everything I've read, the n-3 content and turnover in the brain is is too low to conclude frequent fish is a significant contributor.

Is the total body n-3 turnover much higher, or maybe there is something about seafood/coastal living beyond n-3s? Jack Kruse likes DHA and iodine, but even iodine in high amounts doesn't seem necessary. I think there is an LEF article on iodine, but I remember I wasn't too impressed with the references.

Anonymous said...

Thanks for blogging more frequently. A voice of reason in an insane nutritional climate.

Stan (Heretic) said...

DHA seems to be a unique bottleneck for the development of brain, and not easily or cheaply synthesize'able from other fats. Have a look at this paper:

http://www.ncbi.nlm.nih.gov/pubmed/23206328

john said...

That's interesting. Would we expect a change from something like 50mg/day to 1g/day make a significant difference? That seems like a rough range for traditional diets.

Stan (Heretic) said...

Probably or even most likely! The argument from that DHA paper that the upper limit for herbivores' brain size is 1% of body weight, while higher brain size like 2% (of body) is only attainable by carnivorous animals, is very compelling!

john said...

My friend is sending me the full text. I'm excited.