[From: Bruce Nevin (Mon 930329 14:44:46)]
Chuck,
In my opinion Rick is right on this point and you are barking up
the wrong tree. Whether or not the subject knows or figures out
that there IS something other than her mouse movements that is
making the cursor move is irrelevant to the point being claimed.
In fact, even if you carefully avoid mention of any disturbance,
the subject will presume that there is one, though perhaps not
using that word for it. As a matter of conversational pragmatics
it would be impossible to give a tracking instruction, like "keep
the cursor on this mark", unless it were stated to the subject or
presupposed by the subject that something was liable to separate
the cursor and the mark, otherwise what's the point? If there is
no disturbance to change that relationship, the subject would
justifiably be confused and say "what do you want me to do, sit
and watch as it continues not to change?" The subject is
ostensively presented with a task. The task description calls
her attention to a perception, prescribes a reference value for
that perception, and tells what to do to change the perception
just in case it should move from the reference value. The
obvious necessary presumption, even if the subject is not
explicitly told there will be a disturbance, is that something is
going to move the perception away from the reference value. No
disturbance, no task.
I think you tripped up on an ambiguity in the phrase "information
about the disturbance." You appear to be reading it as
"information that there is a disturbance present." The intended
meaning is "information as to what the disturbance is", that is,
information about the changing moment-by-moment values of the
disturbance as a change of position of the cursor that is added
to the changes due to mouse movements. (In another situation it
could be pressure, light intensity, pitch, etc.)
Bruce
bn@bbn.com