Re: culture as gene-flow regulator: the arunta

Julia E Smith (
18 Sep 1996 20:11:30 GMT

In article <51muh4$>,
Gerold Firl <> wrote:
>This post will put forth a hypothesis about some of the cultural
>adaptations of the australian arunta as they relate to the problem of
>gene-flow regulation in the difficult circumstances of the desert
>outback. These ideas were posted here earlier this year, but I thought
>it might be interesting to summarize them again, since there is a vocal
>opposition to the idea of culture as a functional adaptation currently
>active in the newsgroup. I'll try to show how a sociobiological
>analysis of arunta kinship and marriage customs leads to falsifiable
>predictions about the arunta lifestyle, which in the scientific
>tradition is the best test for any theory.

While falsifiable predictions are indeed a wonderful thing, we have to be
careful about two things:

1. Are we asking interesting and useful questions? Clearly the
interest in this question is in its broader implications. You have
suggested that if your hypothesis is correct, you have demonstrated that
sociobiology can provide useful analyses of human behavior (although you
assert that merely the fact that we can generate testable hypotheses
demonstrates this -- I can hypothesize that the moon is made of green
cheese, but testing it and not rejecting it is the trick ;-). You also
suggest that it will advance the idea that "culture is a functional
adaptation." What are you asserting is "functional" here? Subincision?
Sexual license? The combination? Just something worth thinking about.

2. Your hypotheses need to test one simple thing. As I assert below, you
are conflating several different phenomena in your hypotheses, and you
need to demonstrate each phase to be true. If any of your assumptions
(about the relatedness of individuals, about the relative probabilities
of conception, and about the specific advantages of genetic mixing in this
environment) are false, your conclusions are unjustified. You need to
prove them before you can go on to your actual hypotheses.


>The promiscuous sexual activity at large gatherings would accelerate
>genetic mixing, since matings would occur between individuals who were
>ordinarily more widely separated than typical marriage partners.

The statement that at these gatherings people have sex with individuals
less closely related to them than "typical marriage partners" strikes me
as something that needs to be confirmed rather than asserted. Once again,
it should be fairly easy to interview people, find out how closely related
their spouses are, and then find out how related people are at gatherings.
If there is no real difference between spousal relatedness, and
relatedness of people at gatherings, then your hypothesis is not

However, I suspect that you would raise (and rightly so) a second point,
that the fact that each child has a different pair of parents could
increase the rate of "genetic flow." :-)

>Large-gathering copulations have a higher incidence of male-superior
>positions, leading to higher fertilization rates.
>Young men on walkabout get laid a lot.

It strikes me that before you go interviewing people about rather
intimate details like sexual positions, you ought to begin this study by
confirming that there *is* an increased rate of births nine months after
these large gatherings. If there is no increase, then your hypothesis is
perforce not confirmed. Then you can investigate the mechanics of the