from Francesca Mansfield:

Fire use for cooking is first known from Israel, 780 ka, when fish were cooked over open fires
https://phys.org/news/2022-11-oldest-evidence-cook-food.html https://www.nature.com/articles/s41559-022-01910-z
This could have been H.erectus or some other early Homo (sub)species.

There’s no way meat consumption is linked to encephalisation, or that early Homo would have eaten raw meat (they may have sucked raw bone marrow & brains, but that’s neither here nor there).

Encephalisation began with the appearance of H.erectus, and continued steadily over the next 2 Ma or so, but what we find is that the larger brains were a) coastal/marine-associated & b) cold-water-associated.

I believe that DHA provides the building blocks for a bigger brain, but not necessarily the impetus. Large brains are energetically expensive & dangerous for childbirth, and they really make very little sense. There’s no way that encephalisation
occurred for the sake of increased intelligence – that was just a secondary factor. Most animals manage fine without them, but of course, there are a few exceptions.
-The largest absolute brains: sperm-whales, bottlenose dolphins, elephants etc. -The largest relative brains: human, dolphin, elephant etc. suggest an aquatic connection.

And there is a link between cold water diving & brain growth.
The motivation could be 2-fold:
1) Larger brains maintain thermo-regulation longer than smaller brains,
2) as Gareth Morgan suggested: larger brains can warm the blood which is redirected to the heart – vital if diving in cold water.

Sperm-whales are the deepest cold water mammalian divers.
In humans, the largest brains seem to have belonged to N.Atlantic diving Neanderthals during ice ages.

The first H.sapiens maintained coastal living & aquatic foraging, and brains continued to increase.
Then, c 84 ka, our ancestors seem to have found a way to synthesise DHA from terrestrial resources: that’s when we were able to leave the coasts & aquatic foraging zones, and move inland.
Perhaps that’s when our ancestors really started hunting large game, but in terms of brain sizes, it’s been downhill since then.
We don’t swim in cold water anymore.

____

:-) Thanks, Francesca!



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Oh, JTEM is always disagreeing with everyone...

littor...@gmail.com wrote:

There’s no way meat consumption is linked to encephalisation, or that early Homo
would have eaten raw meat (they may have sucked raw bone marrow & brains, but that’s neither here nor there).

https://www.reddit.com/r/pics/comments/4uitjb/children_of_the_north_eating_raw_reindeer_meat/

https://www.reddit.com/r/pics/comments/8ggean/nenets_children_eating_reindeer_meat_yamalnenets/

Raw seafood is common today, so if we posit a coastal origins then
it would seem only natural that they would go from raw shellfish and
fish (caught or scavenged) to raw animal meat.

I believe that DHA provides the building blocks for a bigger brain,
but not necessarily the impetus. Large brains are energetically
expensive & dangerous for childbirth, and they really make very
little sense. There’s no way that encephalisation occurred for the
sake of increased intelligence – that was just a secondary factor.

Humans were under ever increasing selective pressure for
intelligence.

A diet rich in brain foods doesn't not equate to big brains though,
we can all agree on that much. A diet rich in brain foods maps
directly to brains just as large as genetics will allow. However,
absent selective pressure on larger brains, that's not going to be
very big at all.



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