[sci.bio] Why are Humans as Smart as They Are

janw@inmet.UUCP (08/21/87)

[lonetto@phri.UUCP ]
>But then I look at many modern humans watching Dynasty, at a  to-
>tal  loss  for  how  to  cope,  idealizing  Ollie North (and even
>BELIEVING him), poisoning the water and atmosphere, arguing  that
>"there's  plenty of room for more people" (though aparently there
>isn't enough room for the rest of the species on this planet)

...and even  making political correctness of opinions the
criterion of intelligence... now *that* is really dumb; but see
below.

>and it seems that the larger part of the
>question is indeed "why not smarter?"  

Perhaps it is because *conformity* is a  survival  characteristic
inside a group. Selecting for it also increases the group's cohe-
sion and to this extent makes it stronger.  On  the  other  hand,
conformity  destroys  intelligence,  causing  the group to choose
suboptimal strategies against nature and against other groups.

Therefore, in intergroup competition, a certain  balance  between
these   two  characteristics,  discipline  and  intelligence,  is
selected. 

This might explain both "why smart" and "why not smarter".

Biological and social evolution may well have gone hand in  hand,
nature  selecting  between  competing groups with certain genetic
and cultural characteristics; social factors selecting  indivi-
duals inside a group. Thus, there would be a two-level selection
system, a group being selected for its internal selection methods.

The mechanism may not even depend strongly on how much intelligence,
or any of its preconditions, is genetically determined.
Assuming that biological parents bring the child up, the genetic types
and the role models are selected together.

			Jan Wasilewsky

gallagher@husc4.HARVARD.EDU (paul gallagher) (08/24/87)

A book, perhaps a little out of date, on this subject is R. Lande's
Evolution of the Brain and Intelligence (1973).  But before one starts
making up adaptive stories to explain the origin of any biological feature, it
is important to know precisely what are the traits that you are examining and
to consider the possibility that a given trait is merely the correlated 
consequence of selection directed elsewhere.  For example, it might be a
mistake to regard the human chin as a unitary trait requiring adaptive
explanation; it could be regarded instead as a byproduct of the interaction of
the alveolar and mandibular growth fields, which would lead to a very different
interpretation of its origins (see Stephen J. Gould's Ontogeny and Phylogeny,
pp. 381-382).

Also, it is important not to confuse cultural adaptation (with heritability
imposed by learning) and physiological adaptation (the phenotypic
plasticity that permits organisms to change during the course of their
development) with the sort of adaptation that arises from the action of
selection upon genetic variation.  It is also important not to confuse
the current utility of a trait with the reasons for its origin.  And it
is important to remember that even if an adaptive scenario is plausible,
it should not be accepted as true without *evidence*. 

One elegant interpretation of the origin of human intelligence involves
neoteny: we are permanently juvenile apes.  See Stephen J. Gould's Allometry
in primates, with emphasis on scaling and the evolution of the brain.  In
Approaches to primate paleobiology.  Contrib. Primatol. 5, 244-292.  Also,
see Gould's Ontogeny and Phylogeny. 

PG