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Darwin-L Message Log 1:209 (September 1993)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

Note: Additional publications on evolution and the historical sciences by the Darwin-L list owner are available on SSRN.


<1:209>From ARKEO4@FENNEL.WT.UWA.EDU.AU  Sat Sep 25 21:00:20 1993

Date: Sun, 26 Sep 1993 10:05:05 +0800 (SST)
From: ARKEO4@FENNEL.WT.UWA.EDU.AU
Subject: Evolution Cultural Capacity
To: darwin-l@ukanaix.cc.ukans.edu

We have been seeing quite a bit on Cultural Evolution here, much of it
quite provocative and well-expressed.  But, I must admit, by and large,
the comments are the usual ones I encounter on this topic.  It seems that
one of the major concerns is whether any THING exists which can be said to
serve as the mode of inheritance and selection for culture.  For example:

From: "JOHN LANGDON"  <LANGDON@GANDLF.UINDY.EDU>
Date: Mon, 20 Sep 1993 10:57:38 -0500
> To me, heritable implies genetic or some other biologically determined
> change. Culture is not heritable and the evolution of culture is not better
> than an analogy with organic evolution. What non-genetic systems do you
> have in mind?

I think it is pretty obvious that those of us working in this field take
culture = inheritance system as a given.  Defense of this assumption is not
really that difficult (visit your local anthropology department :{)  ), but
no defense can stand against a principled assumption that heredity *must*
equal genetics and therefore that non-genetic inheritance systems, BY
DEFNITION, cannot evolve.

Howevever, let me note that the evolution of the genetic CAPACITY for
culture provides us with an interesting starting point in understanding the
"naturalness" of the cultural inheritance system, especially for those with
genetic-reductionist tendencies.  One way to look at this is in terms of
what Boyd and Richerson call the "argument from natural origins."  My
version runs more or less along these lines:

Consider that the human *capacity* for culture is the result of GENETIC
evolution which resulted in the various morpological changes characteristic
of our line relevant to this capacity (the normal stuff about larger brain,
etc etc).  Put in rather simple terms, we are cultural *only* because our
genes permit it.  During the evolution of Homo, this genetic capacity for
culture, of course, arose by means of normal, genetic evolution.  The
obvious conclusion to be derived from this observation would be that the
*genetic* capacity for culture evolved because the genes permitting culture
induced fitness.

Consider now that culture is, in its manifestations (as opposed to the
capacity) PURELY PHENOTYPIC -- put in other words, the *specific*
behaviours induced and transmitted through a cultural system are not *in
and of themselves* genetically determined (the obvious example here is
language).  Hence, *any* genetic selection for the cultural capacity had to
the result of selection acting SOLELY upon the mainfestations of that
capacity -- the culturally transmitted behaviours themselves.

Now given the fact that the capacity for culture DID evolve (humans, after
all, are cultural), and given the fact that the establishment of the
cultural capacity required genetic change, and taking into account that it
was not the CAPACITY per se that was selected (recall, the capacity itself
does not exist as a focus for selection, only its manifestations in
specific phenotypic behaviours), we are led to to the following:

During the evolution of the genetic capacity for culture, (at least some)
NON-genetically determined behaviours were of capable of inducing
sufficiently high relative fitness to bring about a populational change in
the genetic makeup of Homo. "Culturing" hominids were more fit than those
whose behaviour was more strictly genetically determined. As a result of
the genetic selection which occured, the human capacity for culture was
established in our line.

Yet the capacity for culture merely means that certain kinds of behaviours
are determined by phenotype/phenotype transmission.  The *specific*
behaviours selected during the evolution of the genetic capacity for
culture were NOT (by definition) genetically *determined*.

But we must recognise that it must have been these very non-genetically
("culturally") determined behaviours which must have been increasing the
fitness of the individuals, else we could never have the evolution of the
genetic capacity to perform them.  The advantages for coding the
determination of certain kinds of behaviours in the phenotypic, cultural,
system were sufficiently great to "drive out" the earlier system which
presumably had a more direct ("hard-wired") genetic determination for
behaviour.

>From this logic we can be *certain* that CULTURALLY DETERMINED behaviours
must be subject to selection  -- else we would never have estabished the
GENETIC capacity for culture.  The genetic capacity could evolve only by
means of the selection of the phenotypic, non-genetic, *expressions* of
that capacity.

>From this, we can see that the selection of cultural behaviours was
sufficent to bring about what amounts to a revolution in the genetic system
of Homo -- culture replaced genes in the determination of much of the
specifics of behaviour.  Clearly, a lot of genetic fitness can arise from
genes "giving up" control over certain kinds of specific behaviours and
instead having genes (?"meta-genes?") which ALLOW the phenotypic system of
transmission.  It therfore seems pretty reasonable to presume that culture
as *expressed* in specific behaviours was sufficiently fit that it could
bring about this kind of genetic change (else we wouldn't observe
culture!).

Now to return to the question of "is culture an inheriance system on which
selection can act?"  It seems that selection of cultural behaviours MUST
have occurred in the past -- else we would not have a capacity for culture.
Yet AFTER the cultural capacity had been established WHY should we presume
that the selection would stop?  Certainly feed-back to the genetic system
need no longer be occurring, but so what?

If the selection of purely phenotypic variants (culture in its various
*manifestations*) was sufficently powerful to bring about the GENETIC
changes typical of modern Homo (the genetic *capacity* for culture), then
why should selection not apply to these same traits afterwards?  How in the
world would selection "know" that the cultural capacity had been
established, and why should selection of these phenotypic traits in their
various manifestations, and hence the potential for evolution, cease?

The obvious rejoinder would be that "without the genetic feedback there is
NO evolution."  While this would provide a neat, definitional solution to
the problem, it would miss the very point of what I am saying: In the case
of the evolution of the genetic cultural capacity, the genetic feedback was
merely a CONSEQUENCE of the differing fitness of KINDS of phenotypes (those
which were more or less "hard-wired" in the determination of behaviour).
GENES, per se, were NOT being selected, phenotypes were.  As a consquence
of the relative superiority of phenotypic coding, genetic evolution
occurred.  Those demes capable of phenotypic coding of behaviour and hence
of phenotypic evolutionary processes were more successful over time.

So, at least in a sense, the evolution of the genetic capacity for culture,
was also the evolution of culture as phenotypic inheritance system which
could be subject to selection, and hence which could evolve.  Had
*HEREDITABLE* differences in phenotypically and culturally based fitness
NOT correlated with the more "culturing" demes, then the selection of their
particular genetic system (the hereditablility of which is NOT under
question by even the most ardent doubters of culturally based heredity,
selection and evolution) would never have occurred!  We would not be
cultural animals.

Dave

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