Re: Brain size, IQ

Richard F. Hall (
Thu, 29 Aug 1996 03:50:39 MST

In article <4vt1qo$> (Bryant) writes:
>From: (Bryant)
>Subject: Re: Brain size, IQ
>Date: 26 Aug 1996 14:35:36 -0600

>In article <>,
>Len Piotrowski <> wrote:
>>In article <4vqusf$> (Bryant) writes:
>>>As Dawkins points out in his _Extended Phenotype_, the association of
>>>larger cranial capacity and apparently increased intelligence in the Homo
>>>lineage suggests (demands) heritability for brain size in past human and
>>>proto-human populations. This is, hopefully, not controversial.

This is only a bit contriversial in that the cranial capacity is not the
ultimate gauge of "intelligence". Apparently the frontal lobes act as "super
chargers" for certain brain activities which are typically included in the
tests for "intelligence". For instance, the Neanderthal had a significant
cranial chamber; however, it was full of cerebellum and temporal lobes. This
indicated a human with incredible coordination and reflexes. Unfortunately,
these aspects are not necessary for a high score on I.Q. tests.

>>I am not familiar with Dawkin's hypothesis, but you would be mistaken about
>>the uncontroversialness of your statement.

>What's controversial about the notion that cranial capacity was heritable
>during human evolution? How else do you explain the dramatic changes in
>head size through time, as evidenced in the fossil record of our ancestors?

Cranial capacity is sort of equivalent to RAM memory in your computer. It
doesn't mean much if your running a 286 with windows 3.0. The idea that
evolution is creating a "meaner-leaner-brain" is true. It may be limited by
biochemical blood-sugar factors involving metabolism, so we can't get too
excited for our genius children - they may all wind up diabetic if they get
too smart.

>Heritability means, evolutionarily, "not fixed." That is, genetic or
>allelic variability is responsible for phenotypic variability for a given
>trait. Once an allele is fixed in a population, heritability is zero,
>because everybody has the same allele for that trait, and phenotypic
>variation in that trait cannot be accounted for genetically.

>>The evolutionary significance of altered developmental ratios for humans,
>>seems to affect the sexes differently. Females appear to experience prolonged
>>developmental growth with respect to males, thus apparently increasing the
>>time and development of the neural net. A byproduct of this developmental
>>retardation may just be something measurable by the human IQ test. Who knows?

The girls develop faster than the boys, initially, when considered as two
groups. This is primarily due to the process of masculinization during
childhood from age six through puberty. After that, the boys rush ahead.
Remember, this does not apply to any particular man or woman. Many women are
so smart that they out think most men.

>I don't follow this. Sorry. Could you reword this?

I agree with Bryant, you should reword your paragraph.


Wouldn't you like to soar like an Eagle?
In the past, philosophy was based on logic and reasoning rather than observations
recorded using the scientific method. Realistic Idealism draws its principles from facts
determined through science. In the past, ostensibly, facts were few and far between.
They were not near enough together to be closely related. To relate them, one had to
bridge long gaps with logic. We now know so much that we can travel great distances
in reason without losing touch with factuality.
To many people, a logical subject is right, and to be right is to be logical. But logic is
a relationship of ideas; ideas that may have no connection with facts. To many people,
a philosophy bound to facts seems laden down. With that limitation, a philosopher
is not free to fly with his imagination. Consequently, a Realistic Idealist needs a
certain humility, for he/she is required to hew to a factual line. In Realistic Idealism,
one does not soar like an Eagle. It is more like exploring a railroad track on foot.
Join our exploration.
richard f hall