Biocultural Evolution

John A. Giacobbe (Catalinus@AOL.COM)
Tue, 19 Sep 1995 02:25:11 -0400

appropriateness of an evolutionary view of culture. Being a
hopeful protagonist of an evolutionary theorem encompassing
all life forms, I would like to respond to a few of the
posting. Lian, Corduan and Loker have noted the problematic
nature of measuring the fitness of a cultural trait, or for
that matter, an entire culture, and Davidson has noted the
perplexity of the time scale used to chart cultural
evolution. I would counter that the word fitness has grown
beyond its britches. The level of fitness is only a measure
of the adaptive efficiency of a behavior for a given
setting. That could involve an environmental setting, in
which one method of food acquisition is more efficient than
another, or it could involve a cultural setting, where the
manufacture of a culturally emblematic tool is a requirement
of cultural acceptance.
This acquired fitness does not imply any type of
superiority. Fitness is only a temporary quality, and with
a change in the ecological setting (both environmental and
cultural ecologies), a behavior that was fit once, may no
longer be so. Neither increased complexity nor any
sequential stages of development are implied. Evolution
occurs, and is influenced, through adaptionary responses
only, and is caused by changes in the frequency or the
expression of a characteristic, but this new expression need
not be either of increased complexity nor a `higher form',
but simply a form that is best adapted to the particular
environment it occupies.
For a very loose example, an agricultural society
(Society Alpha) may be very successful with this behavioral
trait for a limited time, and for that time this trait may
be a more fit expression than that of a another society
(Society Beta) using a hunter-gatherer behavioral trait.
Society Alpha may, for a time, out reproduce Society Beta,
acquire control over more resources than Beta, acquire
control over Beta territory, and a host of other possible
measures of fitness. After some time, the environment may
change, the soil may degrade, disease and malnutrition may
arise, and other events may contribute to reduce the
efficiency of the agricultural behavior. Meanwhile, the
hunter-gatherers may find their mode of resource acquisition
is now a more efficient, and hence more fit, mode of
Evolution does occur in cultural systems. Any denying
that is foolhardy, for evolution simply means a change in
the frequency of a cultural expression. The simple fact
that you are reading this text from a computer, and not from
a piece of parchment, points out a change in the frequency
of cultural behaviors. From an archaeological context, we
can observe changes in frequency of a behavioral trait over
time expressed in artifact counts, and attribute data. The
key to applying evolutionary theory to an anthropological
perspective lies in understanding and identifying the forces
of selection.
Grieger and Tomaso took issue with selective forces,
preferring selective processes, considering that selection
is not directional. I would counter that by stating that
while selective pressure may not always be directional, it
certainly can be.
There are three modes of selection;
1) Stabilizing selection tends to promote maintenance of the
status quo, and functions as long as the environmental and
cultural systems remain in equilibrium.
2)Directional selection acts to guide adaptionary changes to
fit an environmental constraint. It is through this type of
selection that most evolutionary events occur.
3)Diversifying selection acts to favor extremes of trait
expression. It would tend to favor alternate forms of an
expression, and tend to not favor a median form.
Further, I would consider the source of selective pressure;
1)the environment is the primary source of selective
pressure, and is the ultimate test by which adaptions are
measured for their selective value.
2)demographic conditions, such as population size,
geographical distribution, and life table dispersions are
also a source of adaptionary influence. Population
parameters and interactions with the environment are the
principal influencing factors towards adaptive success.

While the bugs aren't all worked out by any means, nor will
they for years to come, I believe evolutionary theory offers
the possibility of a true bio-socio-cultural paradigm.

Sorry I got on a rant

John A. Giacobbe