I had no idea. I was just pointed to it recently from another list.

Good. The experiment is, however, very good evidence for the hypothesis that R.S. Marken is a crank, and explains the >quote from his farewell speech that didn't make sense to me before:

I can be a pretty cranky fellow but I think there might be better evidence of that than the model fitting effort you refer to. The "experiment" that you find to be poor evidence for PCT comes from a paper published in the journal Ergonomics that describes a control theory model that can be used as a framework for understanding the causes of error in skilled performance, such as writing prescriptions. The fit of the model to the error data in Table 1 is meant to show that such a control model can produce results that mimic some existing data on error rates (and without using more free parameters than data points; there are 4 free parameters and 4 data points; the fit of the model is, indeed, very good but not perfect).

But the point of the model fitting exercise was simply to show that the control model provides a plausible explanation of why errors in skilled performance might occur at particular (very low) rates. The model fitting exercise was not done to impress people with how well the control model fits the data relative to other models since, to my knowledge, there are no comparable models of error against which to compare the fit .As I said in the introduction to the paper, existing models of error (which are really just verbal descriptions of why error occurs) "tell us the factors that might lead to error, but they do not tell us why these factors produce an error only rarely."

So if it's the degree of fit to the data that you are looking for as evidence of the merits of PCT then this paper is not necessarily a good reference for that. Actually, a good example of the kind of fit to data you can get with PCT can be gleaned from doing one of the on-line control demos at my Mind Readings site, particularly the Tracking Task. When you become skilled at doing this task you will find that the correlation between the PCT model (called "Model" in graphic display at he end of each trial) and your behavior will be close to one. And this is achieved using a model with no free parameters at all; they are the parameters that have worked for many different individuals and they are now simply constants in the model.

OH, and if you are looking for examples of things PCT can do that other models can't do, try the Mind Reading demo, where the computer uses a methodology based on PCT, called the Test for the Controlled Variable, to tell which of three avatars -- all three of which are being moved by your mouse movements -- is the one being moved intentionally.

The fact that Marken was repeatedly told this, interpreted it to mean that others were jealous of his precision, and continued to produce experimental "results" of the same sort along with bold claims of their predictive power, makes him a crank.

I don't recall ever being told (by reviewers or other critics) that the goodness of fit of my (and my mentor Bill Powers') PCT models to data was a result of having more free parameters than data points. And had I ever been told that I would certainly not have thought it was because others were jealous of the precision of our results. And the main reason I have continued to produce experimental results -- available in my books Mind Readings, More Mind Readings and Doing Research on Purpose-- is not to make bold claims about the predictive power of the PCT model but to emphasize the point that PCT is a model of control, the process of consistently producing pre-selected results in a disturbance prone world. The precision of PCT comes only from the fact that it recognizes that behavior is not a caused result of input or a cognitively planed output but a process of control of input. So if I’m a crank, it’s not because I imagine that my model of behavior fits the data better than other models; it’s because I think my concept of what behavior is is better than other concepts of what behavior is.

I believe Richard Kennaway, who is on this blog, can attest to the fact that, while I may not be the sharpest crayon in the box, I’m not really a crank; at least, no more of a crank than the person who is responsible for all this PCT stuff, the late (great) William T. Powers.

I hope all the formatting comes out ok on this; I can't seem to find a way to preview it.

Best regards

Rick Marken