The recent exchanges between Marc and Rick lead me to pose some questions...and I suspect many will view them as extremely naive and uninformed. So be it.
Regarding the matter of evidence in support of PCT and Marc's comment about the tracking test being insufficient proof, are there experiments other than physical tracking tests that support PCT?
I'm also curious about the nature of such experiments, particularly the experimenter's ability to control all the related variables. In a tracking test, I can see how the tracking behavior can be isolated and the other factors controlled. But in other, less physical settings, I see lots of complicating factors. And they bring to mind the notion of doing "the test" to see if someone is or isn't controlling for a certain perception of a particular variable.
For example, suppose I want to see if someone is controlling for preserving or protecting their dignity or identity or somesuch quality. I might, by way of a test, mildly insult him to see how he reacts. Or I might seriously insult him. In one setting, the person who's been insulted might rise to the occasion and retaliate, preserving his sense of honor or integrity or self-image or whatever. In another setting, say in the midst of a bunch of thugs who are taunting him, this same person might wisely choose to keep his mouth shut. Why? Because he is controlling for other variables as well (which we might call survival or safety or something like that).
Sorry for the long-winded lead in but it seems to me that devising tests of control theory in simple, physical tracking tests is far easier than devising tests of more complicated and complex matters. Why? Because of the difficulty of isolating the task. As a human being, a living control system, I'm not controlling a single perception in relation to a single reference signal. Instead, I'm controlling multiple and interacting perceptions in relation to multiple and interacting reference signals. How, then, does one sort through that complexity so as to devise valid experiments? What might such an experiment look like?