I stumbled across two things yesterday that, in and of themselves, I might not have thought twice about. Reading one after the other, though, sparked a good bit of curiosity.
The first tidbit is from Art DeVany, writing about Vegetarianism, here, and especially this last bullet:
A baby raised as a vegetarian will have an underdeveloped nervous system and a small and poorly functioning brain.
Then while reading The Agile Gene, by Matt Ridley (a fantastically interesting book, by the way), on page 35:
… Surprisingly, the fossil record suggests that there has been a rather steep decline in the size of the human brain during the past 15,000 years, partly but not wholly reflecting a shrinking body that seems to have accompanied the arrival of dense and “civilized” human settlements. …
Ridley goes on to say that the average male Brain of 50, 000 years ago was 1567 cc /1468cc (in females). Today, average brain sizes are 1248 cc (male)/1210 cc (female).
The timing of this brain shrinkage, it seems to me, holds a fairly close correlation to the advent of agriculture. Might that have also been a contributing factor, the beginnings of — and the continued — widespread human ingestion of cultivated grain (and other starchy foodstuffs)?
Just something to ponder. I’d be curious to know how the hunter-gatherer society brain sizes held up against these averages.