Re: The need for theory in PA

Alex Duncan (
6 Nov 1995 15:22:17 GMT

In article <> Paul Crowley, writes:

>> The fact is that most paleoanthropologists don't sit around trying to
>> develop models for the origin of bipedalism. A lot more time is spent
>> trying to understand the adaptations of the hominids for which we have
>> a fossil record. Someday, we'll have a fossils that document the
>> origin of bipedalism. When that happens, we'll see a lot more
>> speculation about the adaptive circumstances the earliest
>> protohominids were dealing with.
>It's the absence of any theory - or even of a desire for a theory
>that us non-professionals find so irritating. We don't mind the
>professionals rejecting the AAT if they would suggest something
>better. But most of them assidously suggest nothing. We can see
>the reasons why they want to "play safe", but they are evading
>their responsibilities to their public and themselves.

I think you misunderstood me. There are plenty of models about the
origins of bipedalism. For the most part these models ask (or attempt to
answer) two questions. 1) What were the ancestors of the earliest
hominids like? and, 2) what were some of the potential advantages of
becoming bipedal? However, generating these models is not what
paleoanthropologists spend most of their time doing. I'm sorry that you
find it frustrating, but most paleoanthropologists would prefer to work
on problems that are potentially answerable with the material at hand,
and currently the origin of bipedalism is not one of those problems.

As far as suggesting something "better than the AAT" goes, you see it all
the time in this newsgroup. HUMAN BIPEDALISM IS AN ADAPTATION TO A
TERRESTRIAL EXISTENCE (as opposed to an arboreal existence or a
semi-terrestrial existence).

Paleoanthropologists are not "playing safe" by not suggesting models for
the origin of bipedalism. Lots of models have been suggested. I suspect
the real problem is that you are not familiar enough with the field to
know what the models are (observation, not insult).

I predict you will see a good deal of new speculation about the subject
when the rumored postcranial remains of A. ramidus are published.

>In a few years or decades the answer will be clear. I am sure that
>you will then look back and kick yourself for not realising it;
>because enough of the facts are known now; and the AAT has a
>better attitude to most of them than you do.

There's a greater problem here than I think you realize, and it has to do
with our expectations of what science can accomplish. You seem to want a
definitive answer WHY hominids became bipedal. I do not think that we
will ever be able to answer that question. Even if we had a
time-machine, we would still be asking "why did the proto-hominid leave
the tree?" We can offer potential models and suggest possible adaptive

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086