The details

From Greg Williams (920329)

Bill Powers (920328.1030)

A very nice post, with which I agree almost completely. By that, I mean that I
agree with the basic, underlying, important points. As you note, the DETAILS
are all important. I have one question about the details of your cockroach
"escape" example.

Even if if we used a microanemometer to measure the puff of air itself
instead of the stamping of the foot, we would erroneously conclude that
g(r) = 0. We have to measure the puff of air where the measurement is
relevant: we must mount the anemometer on the cockroach's body next to the
hair in question. The only relevant movement of air is the movement
relative to the hair, in a frame of reference that is attached to the
cockroach. When we make that measurement, we find that g(r) is no longer
zero. There is feedback. In fact, the "escape response" drastically
modifies this relative air velocity while the response is in progress.

Are you claiming that there is actual data showing that (a) in the case of
short-duration air puffs, the body orientation changes before the air puff is
over, and/or that (b) if the body orientation does change before the (say,
somewhat longer-duration) air puff is over, the movement of the cockroach is
actually influenced by the change in alignment between the body and the
continuing air puff? Or are you hypothesizing that feedback would be shown in
this example if someone did the appropriate experiments (which might or might
not actually have been done)? Or are you just making a rhetorical point and
postulating that feedback is there in your exemplar case to help make the

I don't care in the least whether some responses are indeed unitary and
some stimuli are instantaneous, whether g(r) is zero or nonzero, or what is
found really to be the case. What I'm concerned with is getting away from
the sloppy habits of observation that have led to S-R theory as it now
exists, the projection of inappropriate kinds of interpretation onto the
very act of taking data, so that the wrong processes are noted and the
absolutely critical ones are glossed over as "mere detail."

Yes, yes, yes! Everyone needs to "ask the organisms," not themselves!!

I claim that in fact, g(r) is nonzero in essentially any kind of behavioral
situation that can be found. Every response alters the very stimuli that
lead to it immediately and strongly. The real stimuli, that is, not the
ones seen through the abstractions of casual and subjective observation.
Given my claim, the remainder of HPCT follows. Make any model you like of
the organism's interior. But it must be able to operate when g(r) is other
than zero.

There ARE a lot of cases where g(r) is demonstrably nonzero. But it is quite a
leap to your general claim. I wish you could see that the worth of HCPT
modelling does not hang on the truth of that generality. In fact, I think
leaving the question of the truth of your generalization open, at least for
now, would boost the credibility of HPCT ideas for many behavioral scientists.
It is a matter of admitting humility until the data are in. That humility in
no way compromises the significance of HPCT in explaining organismic CONTROL,
when it is actually found to be present.