Re: Big Brains

Michael McBroom (
Tue, 14 Jan 1997 09:51:55 -0500

B Gilmour wrote:
> I read an article a few years back from a theorist (cant remember his
> name, I think he was Scandinavian) that said that large brains in humans
> evolved as heat radiators. It essentially said that when humans made the
> transition to the open savannas, heat dissipation became a major problem
> (nakedness was one solution). Over 70% of body heat is dissipated through
> the head. This was a result of mans mode of survival which required social
> groups while hunting.

< . . . >

> Large brains are normally explained in traditional theories as an
> adaptation evolved for speech (communication), binocular vision,
> socialness, tool making, and others. But I suspect that a large brain could
> have evolved for this more concrete reason, and the other traits are
> exaptations that have found utility within the confines of a larger brain.

You're probably referring to Dean Falk. She was the first, I believe,
to propose the "radiator theory," and asserts that evidence of an
expanded system of blood vessels in the brain is first observed in early
Homo, but not in Australopithecus. It should be noted that hers is
still a quite controversial view. I have only one cite to offer: "A
good brain is hard to cool." _Natural History_ 102(8): 65.


Michael McBroom
CSUF Linguistics