Anthropology

Judi Lynn

(160,542 posts) Wed Apr 10, 2019, 02:37 AM Apr 2019

The Human Brain Has been Getting Smaller Since the Stone Age

By Bridget Alex | April 8, 2019 5:15 pm

I don’t mean to alarm you, but the average human brain size is shrinking. And we can’t blame reality T.V. or twitter. No, this decline began tens of thousands of years ago.

It’s something of a well-known secret among anthropologists: Based on measurements of skulls, the average brain volume of Homo sapiens has reportedly decreased by roughly 10 percent in the past 40,000 years. This reduction is a reversal of the trend of cranial expansion, which had been occurring in human evolution for millions of years prior (see chapter 17).

Let’s review the boney evidence backing this observation, then explore some potential explanations.

And just to ease your anxiety: Although you may have a smaller cranium than our Stone Age predecessors, human brains today are still about three times the size that’s normal for a primate with our body weight.

More:
http://blogs.discovermagazine.com/crux/2019/04/08/human-brains-have-shrunk-since-the-stone-age/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A%20DiscoverHumanOrigins%20%28Discover%20Human%20Origins%29#.XK2OvJhKjIU

4 replies

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The Human Brain Has been Getting Smaller Since the Stone Age (Original Post) Judi Lynn Apr 2019 OP

I prefer the term "leaner". gtar100 Apr 2019 #1

There is a theory that human ancestors ate marrow and brains of applegrove Apr 2019 #2

But also wrinklier I assume, right? That is where human intelligence lies I think. ck4829 Apr 2019 #3

Taken to extremes True Dough Apr 2019 #4

gtar100

(4,192 posts)

1. I prefer the term "leaner".

Reply to Judi Lynn (Original post)

Wed Apr 10, 2019, 02:52 AM

Apr 2019

applegrove

(118,677 posts)

2. There is a theory that human ancestors ate marrow and brains of

Reply to Judi Lynn (Original post)

Wed Apr 10, 2019, 03:02 AM

Apr 2019

beasts felled by other carnivors which is why their brains grew 70% bigger. We were scavengers. The marrow and the brains were the only thing the hunting carnivores could not eat. Humans could crack open bones with tools once the carnivores had left because they had hands and stone tools. The brains and marrow were a bit protected from spoiling as fast as the meat. They also contained building blocks for proteins like amino acids and fats.

Maybe 40,000 years ago the humans were hunting the big game themselves and maybe eating less marrow and brains? Then farming started.

Could be what happened.