Promote a cruelty-free lifestyle long enough, and you’ll eventually bump into the expensive tissue hypothesis. No, it’s not a pet theory about the rising cost of toilet paper, but the claim (usually foisted upon you by paleodieters or some carnist who took an anthropology class once) that meat-eating made humans into the big-brained rocket scientists we are today. How ungrateful and unnatural you are to reject millions of years of evolution. Surely, your brain has shrunk from lack of essential fatty acids, to even entertain such a notion as eating vegan.
To be fair, that last bit isn’t actually the expensive tissue hypothesis (ETH). It’s just the pop culture meme that grew out of an influential idea first put forward by Leslie C. Aiello and Peter Wheeler in 1995. While “meat made us smart” is not, as you’ll see in a moment, actually what Aiello & Wheeler said, it is the message that carnist mainstream society took from the paper and ran with. It’s been the urban caveman’s naturalistic fallacy of choice ever since.
But as with many things in modern science, things look a lot different in the field today than they did 18 years ago. The idea that meat-eating was essential to the evolution of human intelligence isn’t holding up as well as your average broscientist thinks it is. What follows is a slightly edited re-post from my usual blog that explains all the details.
“Energetics and the evolution of human brain size,” published in the November 2011 edition of Nature, tests and refutes the expensive tissue hypothesis. It’s impressive work, and pretty devastating to the hypothesis that has provided a rhetorical foundation to the paleo diet mythology for over a decade now.
Their conclusion: when adiposity, phylogenetic relationships, sample bias and sex differences are controlled for, Aiello’s & Wheeler’s original data don’t support their hypothesis any better than the newer data does! In short, the ETH is wrong at the foundation, not just at the margins.
building a world
“building a world of concrete”
read the cement truck sign
as I look out my bus window
sitting on plastic
gliding in a walled enclosure
upon round oil-infused rubber
gazing out glass
as the automated humans
in Sunday’s best
and not Sunday’s best
(both shipped across the ocean
or maybe within the homeland
walking in rhythm
on the stiff concrete sidewalk
(“building a world of concrete”)
with determined moss in cracks
along cookie cutter dwellings & dealings
and inserted ornamental trees
(from hybridization for preferential traits
or seeds stolen from a far off ecosystem)
with squawking invasive aviators
perched on safe nonnative branches
bartering with automated humans
“A revived sense of nature connection
for industrial lifeless foodstuff.”
scavenger birds & squirrels,
civilized humans and their
pampered pet dogs -
the dominant vertebrates,
desperate fools, dormant beings
in this dead constructed world
(not the animals)
atop foundations of
of dug out ‘dirt’
turned concrete pits.
“building a world of concrete”
(Quick, please tell me, it’s urgent –
where is the nearest living soil?
I need to be there now.
Panic subsides. Longing fads.)
my eyes search
for anything real
finally resting on the one and only
baby blue with wispy clouds
the sky is still real