Physiological Control Mechanisms

yWPC< they termed a "set
     point control system" must contain a specific, _neural_ device
     that provided a neural reference signal, a neural perceptual
     signal, a specific, neural device that functioned as the
     comparator, and a neural error signal capable of driving the
     output so as to correct errors both positive and negative.
     When they did not find such devices and signals within the
     physiological matrix supporting control of body weight, or
     caloric intake, or what have you, they believed they had
     encountered strong evidence against a control-systems model.

Bruce, you seem to be saying that the control systems model does
_not_ require the assumption of actual control system components at
the level of physiology. This is news to me. Chapter 6 of
Robertson and Powers'_Introduction to Modern Psychology_ (1990)
explicitly articulates this assumption, and even reprints as Figure
6.5 a diagram from B:CP postulating a specific model of such
components in the cerebellum. I think Bill Power's hunch that
these researchers are covertly responding to B:CP is therefore
correct. Furthermore, it is clear from his reply to your post that
Bill still holds this assumption, and believes that there _is_
evidence for such physiological mechanisms. Bill wrote
(960520.0630 MDT):

     Booth uses lack of supporting evidence for control-system
     components as proof that they don't exist. Actually, I wonder
     what he means when he says there is no evidence. I thought
     there was quite a bit of evidence, for example in the
     literature on reflexes and specifically control-system
     analyses of reflexes, with at least some preliminary

On two occasions on this net I asked what has been done to
substantiate the kind of speculation about physiological mechanisms
in B:CP. I got no answer. Tom Bourbon is currently working in
this area, but when I asked him about empirical research, he said
that control theory was not nearly as well established in
physiology as Bill Powers seems to think. In fact, Bruce's
quotation from D. A. Booth in the same post I quoted above
indicates the opposite. Bill, since you recently said on this net
that you were looking for collaborators on PCT research, why don't
you work with Tom on these sorts of questions? Do you not agree
that empirical work of this sort is foundational to PCT?

Best regards,