[Martin Taylor 2007.09.08]
[From Rick Marken (2007.09.08.1520)]
> Martin Taylor (2007.09.08.12.51)
To this point, I see no difference between a PCT approach and the
The difference is the assumption that it is the value on the response
dimension -- N in this case -- that is perceived as matching the
magnitude of the stimulus. What we are saying is that it is the
_perceived_ value of N -- Pn -- that is perceived as matching the
perceived value of the stimulus. The difference between the PCT and
conventional approach is that, in PCT, it is assumed that the subject
is controlling for Pn = Pi; in the conventional approach it is assumed
that the subject responds with N = Pi.
I guess you have been skimming, rather than reading, my posts. The whole point of the summer student work that I discussed, and of my thesis, was that the matching was of perceptions -- perceived value of N, of grey value, of time difference, of hue, or orientation ... -- that mattered. The notion was even then that a dimension used as response was perceptually different from the same dimension used as stimulus. That would have made no sense if the response represented a phsyical rather than a perceptual magnitude. To understand this has nothing whatever to do with control.
> All that is asserted is that somewhere inside the
subject there is the possibility of comparing the magnitudes of two
perceptions of different kinds. Again, that's conventional
I don't believe that conventional psychophysics treats the subjects'
"responses" as a perception, let alone one that is part of a
I think you go overboard in your denigration of conventional psychologists and what they think. Yes, most don't think of behaviour as the control of perception, but in the sort of experiment we are talking about here, I don't think they are as naive as you suggest. I mean, even in 1923, Thurstone could write a paper titled "The Stimulus-Response Fallacy in Psychology" <http://www.brocku.ca/MeadProject/Thurstone/Thurstone_1923.html> in which he says:
I am calling in question the stimulus-response formula which is explicit or implied in much of our psychological writing
Let us start the causal sequence with the person himself. Who and what is he? What is he trying to do? What kind of satisfaction is he trying to attain? What are the large types of self expression that are especially characteristic of him? What are the drives in him that are expressing themselves in his present conduct? Let us consider the stimuli as merely the environmental facts in terms of which he expresses himself.
I have listed a number of stages in the development of psychological acts in which they may be identical or similar. If we start with action at its source and follow the stages through which it becomes formulated into conduct, and the consequent satisfactions, we shall have a table as follows:
THE STAGES OF THE PSYCHOLOGICAL ACT
(I) Energy source
(2) Reduced threshold for stimuli
(3) Deliberate ideation
(4) The internal stimulus
(5) Imaginal hunt for external stimuli
(6) Overt hunt for external stimuli
(7) The external stimulus
(8) The consummatory overt act
(9) Overt consequences of the act
(10) Satisfaction to the actor, and quiescence at the energy source
(I) The energy source is the dissatisfaction in the physiological, mental, and social conditions which provokes action. These physical and mental conditions cover such wants as the satisfaction of hunger, bodily comfort, sex, social approval, social power. A state of dissatisfaction in any one of the instinct conditions is the starting point for action which is maintained until satisfaction is attained. Two actions belong in the same instinct category if they can by conditioning be readily substituted for each other.
(Gary...Maybe this article might qualify for "almost PCT"?)
I got the impression in graduate school that Thurstone was something of a hero to at least some of the faculty.
Back to the main theme. A response may not itself be considered to be a perception, but the assumption always is that it corresponds to a perception of some kind. Is this assumption chanbged by rercognizing that the response is an act that serves to control a perception of the experimenter being pleased that the subject is performing the experiment as intended? The act of responding cannot, in itself, influence the perception of the stimulus the experimenter presents, but if it turns out to be logically inconsistent with other responses, affect subject's perception of the experimenter's satisfaction. The easiest way for the subject to be consistent is to report something which (s)he perceives as bearing the correct relation to the stimulus. That's just a long-winded way of saying that from a PCT point of view the subject is doing what most psychophysicists would expect.
I don't think it's necessary to assert all the (imagined or real) failings of "conventioal psychologists" in order to advance the study of Perceptual Control Theory. It can stand on it's own feet, and from time to time can usefully take note of results obtained by "conventional psychologists". The data are there, and if the experiemnt is accurately described and is appropriate, why not use it? That the experimenter didn't know PCT is irrelevant.