Re: what does bigger brain mass mean?

Ralph L Holloway (rlh2@COLUMBIA.EDU)
Sun, 5 Feb 1995 21:23:50 -0500

As far as I know, the differences in brain mass are distributed evenly as
Mike suggests, i.e., cortex, cerebellum, hippocampus, etc. There is no
good evidence for 'reorganization' in different populations with regard
to brain size differences between widely separated latitudes. The larger
size in colder climates has more to do with lean body mass as far as I
am aware. This does not mean that there not differences in organization
(and I do know of one, which I will post later), but it isn't related to
size per se. As for who studies these problems, almost no one does.
There is too much trouble associated with the study of the brain that
attempts to study either sex or ethnic ('racial') differences in either
quantity or organization.
On Sun, 5 Feb 1995, Mike Lieber wrote:

> I've been following the discussion of brain development with interest. I miss
> what appears to me to be crucial data in this discussion. What, specifically,
> does a lager brain mass in one population, as compared with other populations,
> mean? If people in cold climate develop larger brain mass than those in
> warmer climates, does this mean that they have more brain cells? If so, how
> are these "surplus" cells distributed? Do they all go into the cerebral cortex
> or are they distributed, say, evenly through the cerebellum, the medulla, the
> cerebrum, etc.? Does anyone know? Has anyone asked? Is anyone looking?
> If larger brain mass does not mean more brain cells, then where is that extra
> mass located and what are its constituents? Given that more heat is lost
> from the head than from elsewhere on the body, might that larger mass not have
> something to do with heat conservation? If so, then I would suppose that
> extra brain cells be maladaptive, given that the resources that added mass
> requires would be taken up by processing rather than by insulation. More
> brain cells in a cold climate would pose a problem of oxygenation as well as
> insulation.
> Isn't the question of intelligence premature until these substantive questions
> are answered?
> Mike Lieber