From “Monkeys did not gain big brains by shrinking guts” (New Scientist, August 11, 2011 ) we learn that some doubt has been cast on the theory known as the (“expensive tissue hypothesis”), that eating – and cooking – meat helped us develop big brains. That’s because digestion became a less cumbersome process. Howver,
Kari Allen and Richard Kay of Duke University in Durham, North Carolina, turned to New World monkeys to explore the hypothesis. Previous studies offer a wealth of data on the monkeys’ diets and show that their brain size varies greatly from species to species. But when the pair controlled for similarities between related species, they found no correlation between large brains and small guts (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2011.1311).
Oxford critic Robin Dunbar responded, “It is one thing to say that the hypothesis doesn’t apply to New World monkeys, and another to extrapolate that to humans.”
But people do that all the time, Robin. It’s the sport called “human evolution.” If lemurs eat their young under stress, we have an instant theory in the making about why women may yell at their children more often if they live in a war zone. And that theory is just fine with everyone. But let something more specific, like the “expensive tissue hypothesis” be disconfirmed, and we hear … heck, we just heard it.
See also: Flores man really was microcephalic, researchers say