Control means bringing one's perception closer to one's reference
signal. One limitation of PCT as far as I can yet see is that the
model offers no predictions as to how choices of shift in reference
signals affect disturbance levels. By the way, I share the assumption
that perception controls behavior, and haven't in any way meant to
question the importance of that assumption. It works for me too, up
to a point. Ultimately, though, causality is fully recursive, meaning
that one can only distinguish causal directionality of shifts in
perception-behavior interactional products.
And Bill P., I seem to have a way of drawing expletives out of you. I
imagine we'll give a little more substance to these differences of
ours as time passes. Your operational variables are, I believe,
material purely--the kind of change machines can register. You
presuppose linearity of causality (perception causes behavior). These
are, I believe, definitive of characteristics people associate with
the left brain. I consider "left brain" a metaphor only. Of course
none of us is one or the other; at least I posit we cannot
meaningfully separate independent effects of left and right thinking.
I'm therefore being a bit facetious about what part of your brain is
turned on and off. Please don't take offense. I hereby disclaim all
knowledge of which of your brain circuits are firing 
l&p hal