For the time being I must
focus on my thesis and can unfortunately not engage much in somewhat
off-topic issues.
One short reaction is that I think human error is a problematic concept.
This concept is an important part of the argument in your paper on faulty
medication to bring your PCT views to the front. The ‘error’ problem makes
the PCT arguments less relevant for me (in aviation). Furthermore I think,
human error is more of a component failure that a systemic failure and that
limits your interventions. Safety science, at least the school I am part
off, has moved to a systemic approach.
When human error is taken a unproblematic your examples of PCT are
impressive.
Back to my thesis,
Thanks
Arthur
-----Oorspronkelijk bericht-----
Van: Control Systems Group Network (CSGnet)
[mailto:CSGNET@LISTSERV.ILLINOIS.EDU] Namens Richard Marken
Verzonden: zondag 16 augustus 2009 23:18
Aan: CSGNET@LISTSERV.ILLINOIS.EDU
Onderwerp: Re: PCT in Human Factors
[From Rick Marken (2009.08.16.1420)]
Bill Powers (2009.08.16.0832 MDT)
Arthur Dijkstra (16-08-09 09:09)
AD: Do you agree with the usage and application of PCT in this paper ?
http://pubs.drdc.gc.ca/PDFS/zbb55/p506682.pdf
If not how is PCT misinterpreted ?
BP: Hendy is a former colleague of Martin Taylor at DCIEM in Canada, so we
can
presume that he has more than a passing knowledge of PCT. When I read
papers
like this, where PCT is embedded in a system of thought thats uses
entirely
different terms and meanings, I mainly look for what is right, and there
is
a lot of that.
I didn’t see all that much that was right with it. They did get the
control theory diagram right. And they did correctly note that the
system acts to keep perceptual representations of the environment in
goal (reference) states. But I don’t think it’s really right to say,
as they did, that their matrix representation of the functions and
vector representation of the variables is a representation of the
“hierarchy of control”. There is no hierarchy shown, or used in the
analysis. I think they also inappropriately superimpose ideas from the
IT model onto the control model. For example, they say that transport
delays in the PCT model could be said to depend on the amount of
information that has to be processed in going sensory input to
perception and from error signal to output. Ignoring that fact that
this implies that information is actually something that control
systems “process”, I think PCT would say these transport lags have
more to do with the level (in the control hierarchy) of the perceptual
variable under control (see my
http://www.mindreadings.com/ControlDemo/HP.html for a demonstration of
this phenomenon) rather than with the amount of information being
processed.
My main problem with the paper, though, is that they don’t really
use the PCT model for much other than to say that a portion of the
control loop could be called a “mental model”. That is, the model is
used as a metaphor rather than as a working model of an observed
behavior. As a human factors engineer myself I wouldn’t know what I
had learned from this paper about the usefulness of the PCT model. The
only data presented is a factor analysis of a couple of tests. This
analysis is kind of thrown in at the end, apparently so that there
would be some data to show. But I don’t know how the analysis is
related to PCT or what I would do with the analysis based on the
observed results.
I may be biased but I much prefer the three papers I wrote that apply
PCT to human factors issues:
Marken, R. S. (2005) A Model-Based Approach to Prioritizing Medical
Safety Practice, in K. Henriksen, J. Battles, E. Marks & D. Lewin
(Eds) Advances in patient safety: From research to implementation,
Vol. 2, Concepts and methodology. AHRQ Publication No. 05-0-21-2.
Rockville, MD: Agency for Healthcare Research and Quality, 409-424
Marken, R. S. (2003) Error In Skilled Performance: A Control Model of
Prescribing, Ergonomics, 46(12), 1200-1214.
Marken, R. S. (1999) PERCOLATe: Perceptual Control Analysis Of Tasks,
International Journal of Human-Computer Studies, 50, 481-487
I’d be interested in hearing Arthur Dijkstra’s impression of any or
all of these papers.
Thanks
Best
Rick
–
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com