From: szabo@techbook.com (Nick Szabo)
Newsgroups: rec.arts.sf.written,rec.arts.sf.science
Subject: Re: Are the Moties us?
Date: 19 Aug 92 08:25:25 GMT
Article-I.D.: techbook.1992Aug19.082525.10080
Organization: TECHbooks --- Public Access UNIX --- (503) 644-8135

In article <1992Aug12.201344.6642@oracle.us.oracle.com> mfriedma@uucp (Michael Friedman) writes:
>Consider:
>
>Up until quite recently the optimum genetic strategy for a human
>female was to have a few kids and concentrate on them.  The optimum
>strategy for a male was to have as many by-blows as possible but to
>also have a small family that he concentrated his effort on.
>
>This is no longer the case in most developed countries.  

True, but the timespan for this change is a few decades.  The timespan
for genetic changes is counted in the generations, and if they are
complex structural or behavioral adaptations we are talking thousands
of generations.  Simple changes of frequency of current alleles can
have effect in just a few generations, but these are often quite limited
in scope and are often regressions to some previous adaptation.

>In the US today, if you have a family of twenty kids you won't have
>fun but you will probably bring all, or the fast majority of them, to
>maturity.  That means you will have a larger share of the next
>generation.  This is true for both men and women.
>
>...
>If I am right, we would expect the following effects....
>
>1.  Women having children at a younger age

True only in that women seem to be maturing about one year sooner than
in previous generations, possibly due to an abundance of food (and this
may be an existing genetic adaptation to abundance).  However, despite
the "epidemic" of teenage pregnancies far fewer are having babies in
their teens than in previous centuries (eg in nineteenth century, being
married and having two or three kids by age twenty was common for women).

>2.  More women having children without husbands - after all, the male
>is no longer so important and you only have so many child bearing
>years.

Perhaps, but there are so many cultural factors here it's hard to tell.

>3.  More premature births - we can take better care of them now
>outside the womb and if you pop them out early you can have another
>kid sooner.

Doubtful.  The genetic advantage of shaving off a few weeks is
infinitesimal, but the costs high regardless of abundance.  There has
been no time to genetically adapt to modern medical technology.

>4.  Women having more kids

Women are having far fewer babies.  The human historical average was
nine per woman per lifetime, with only two surviving to themselves
have children.  The current average in the developed world is
significantly less than two.  

Genetic adaptation to birth control might take the form of those least
skilled in its use having more babies, so that mental and motor handicaps in
general might be selected for.  There might also be shapes of the
reproductive system that could be selected for.  But again, the 
time for genetic adaptation has only been one to three generations in
most cases, so only the most simple of gene-frequency changes will
have occured, not complex adaptations.

>Until something happens to forcibly restrain humn breeding I would
>expect to see a continuing trend that brings us closer and closer to
>the Motie model.

The cultural evolution of birth control has and will continue to far
outstrip genetic responses to it.   Whether those genetic responses
will have undesired side-effects is quite another matter; something
we should look into. 

The main concern of population growth will soon become not our doubling
time, but our _halving_ time.  Consider a space colony.  It will
have the same patterns as any other developed, educated society from
Japan to Italy to Hungary, that is it will have a below-replacement
birth rates.  Space colonies are inherently self-genociding, and no
society has come up with a solution to this problem.  Until we do,
the very concept of an expanding human civilization is in question, but
due entirely to human motivations and choices, not to resource
constraints.  As you pointed out, many of us could get away with having
20 kids, if we were really motivated as evolution would have us
motivated, to maximize copies of our genes.  Instead, we in 
developed/educated populations have less than 2.  This, not overpopulation, 
is the main demographic trend that is shaping our future, and it goes
way beyond simplistic Malthusian formulations to the very heart of
our civilization, our social groups and our values.


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