re: human brains

[Bill Adlam <wa105@mead.anglia.ac.uk>]

Darren Naish wrote:

>>Yeah, female _Homo Sapiens_ usually has a smaller brain than a male of
>>that species
>Actually, female humans have proportionally bigger brains than the 
>males. Or so it says in all the feminist literature I read.

Both true.  Larger vertebrates almost always have absolutely larger but 
relatively smaller brains than smaller members of the same or related species.  
And of course male humans tend to be larger than females of the same age, 
except around 12 or so.

A man or boy has (on average) as large a brain as a woman or girl of the same 
size.  Not _exactly_ as large, of course, but it depends on whether you measure 
height, wet mass, dry mass, ideal mass, whether you discount adipose tissue and 
blood, how you prepare the brain (e.g. removing the membranes)...

I've had a lot of work recently and missed the start of this thread, but I 
guess it has something to do with inferring some aspect of mental performance 
from brain size.  To the best of my knowledge, no correlation has ever been 
demonstrated between IQ and brain mass within the normal human range (say, 99th 
percentile).  There are of course pathologies and teratologies which can lead 
to unusually large or small brains and have severe effects on reasoning.

                                                        All the best,

                                                                        Bill