Re: Brain Temperature Control & A. Africanus

Doug McKean (
Thu, 24 Oct 1996 13:18:21 -0400

Bill Weaver wrote:
> I recently caught a documentary that addressed an interesting idea
> relating to the origins of human intelligence. It started with the
> idea that man's upright posture was mainly a solution to a thermal
> problem sparked by an abrupt change in climate. However, once the
> upright posture was attained and the thermal circulatory systems that
> regulate brain temperature adapted to this new posture (which can be
> seen from brain casts to have occurred between A. Afarensis and later
> gracile australopithecines such as Africanus) the side effect of this
> adaptation was that larger brain sizes could now be supported because
> they could be cooled.
> Does anybody know of a good article addressing the impact of these
> findings regarding the re-routing of the brain's circulatory system,
> which appears to connect A. Africanus quite directly with us? The
> evidence for and against the role of Africanus in our direct ancestry
> was not discussed in detail.

As you may well already know, you are referring to
"encephalisation in australopithecines" which has two things to consider:

1. The development of an increased cooling system necessary
for the sensitive intra-cranial nervous system was the driving
factor for increased brain sizes.
Commonly known as the "radiator theory".

2. Diet may well have been a serious factor in the development of
of the cooling system for the brain.

A Dr. Peter Wheeler gave a presentation at Cornell on this
specific topic sponsered by the Dept of Psychology.

Perhaps you could contact them.

Doug McKean
The comments and opinions stated herein are mine alone,
and do not reflect those of my employer.