PCT Research?

[From Bruce Abbott (950601.1635 EST)]

Rick Marken (950601.1100)] --

Bruce Abbott (950601.1040 EST)

I'd very much like to know whether or not my description of your position
was accurate.

Sorry. The reason I gave no response is because there was no disturbance.

So, whenever you give no response, can I assume that you agree with what
I've said? Thank's for the clarification: does this mean we'll have to find
something else to argue about? (;->

Bill Leach 950529.21:34 U.S. Eastern Time Zone --

OK, I suppose that we have all had about enough of this one and I'm not
sure that all the feathers will be smoothed back down at this point
regardless of what happens.

I don't know about anyone else's feathers, but mine seem to be in good
condition. These debates can and sometimes do become rather heated, but
that's to be expected when two people are trying to get points across that
may challenge each other's conceptions/beliefs; it can be extremely
frustrating at times, both when you feel that your views are being
misperceived or misrepresented and when you feel that you just aren't
getting what the other guy is trying to say. But at times it may be the
only way to really break through and come to some understanding (although
not always agreement). I don't take it personally, and I hope my statements
are not taken personally by others. In my view, it's all just part of the
game. It's hot in the kitchen, but that's where all the cooking gets done.


Now that we know what real PCT research looks like, here's a bit of PCT
research from the 1970s: you know, the kind that focused on identifying the
controlled perceptual variable. Rats were exposed to a schedule of brief
footshocks presented at random at an average rate of once per 120 seconds.
In one condition these were each immediately preceded by a 5-second warning
tone and the houselight illuminating the experimental chamber was on
(signaled shock condition). In a second condition the shocks occurred on
the same schedule but without warning and the houselight was off (unsignaled
shock condition). After being exposed to each schedule alternately for
several sessions, the rats were placed in the unsignaled condition. By
pressing a lever in the chamber a rat could switch from the unsignaled to
the signaled shock condition (indicated by onset of the houselight. Any
shocks that occurred in the signaled condition were, as in training,
immediately preceded by the signal. Further responses on the lever during
the signaled condition had no programmed effect. One minute later the
signaled condition terminated (the houselight extinguished) and the rat was
automatically placed back into the unsignaled condition. By responding
immediately on the lever at this time, the rat could immediately return to
the signaled condition for another minute, and so on.

What happened was that the rats pressed the lever quickly and reliably
enough to spend 85-95% of session time in the signaled shock condition.

I maintain that this experiment performed the Test for the controlled
variable. So long as the signaled schedule remained in effect, the rat did
nothing on the lever. However, as soon as the unsignaled schedule replaced
the signaled one, the rat immediately approached the lever and pressed it,
thus returning itself to the signaled shock condition. The controlled
perception was the schedule in effect (as indicated by the state of the
houselight), the reference was "signaled schedule in effect," and being
automatically switched from the signaled to the unsignaled schedule
constituted the disturbance. The experiment showed that the rat would
defend against this disturbance by pressing the lever to cancel it.
Variables (dependability of stimuli as predictors of shock and safety) were
manipulated across blocks of sessions in an effort to identify which
specific variables distinguishing the signaled and unsignaled schedules were
being controlled. [Badia, P., Harsh, J., Coker, C. C. and Abbott, B.
(1976). Choice and the dependability of stimuli that predict shock and
safety. _Journal of the Experimental Analysis of Behavior_, _26_, 95-111.]

Apparently I was doing PCT research (testing for the controlled variable) as
far back as 1973, when this study began. (;->



[From Rick Marken (950601.1900)]

Bruce Abbott (950601.1635 EST) --


Yes, in the same way that all operant research is early PCT research. In
operant research, the subject is able to influence (operate on) some
variable that affects the subject himself. In the simple operant conditioning
situation, the subject is able to influence food delivery (via bar
pressing) that affects how much food the subject gets to eat. In your
study the subject is able to influence shock signalling schedule that
affects how much shock the subject can avoid.

A disturbance to food delivery in the simple operant conditioning
situation is a change in schedule and we know that the subject will
compensate for these changes (when the schedule disturbance is not
extreme) by changing actions in the way required to maintain food
delivery rate constant. The disturbance to shock signalling schedule in your
experiment was a change in the shock signalling schedule and we see that
the subject did compensate for this change by pressing the bar, restoring
the shock signal schedule in which the shock was signalled.

What happened was that the rats pressed the lever quickly and reliably
enough to spend 85-95% of session time in the signaled shock condition.

This is a nice piece of data because it provides at least a rough measure of
control. The presumed controlled variable was in a particular state 85-95%
of the time; if the rat had done nothing the controlled variable would have
been in that state only, what, 50% of the time? So the control loop is
definitely keeping shock signalling schedule under control.

I maintain that this experiment performed the Test for the controlled

Yes. I agree, your experiment definitely involves the Test. I do think you
could have spent more time nailing down the controlled variable, though.
It seems like there were some other very plausible possibilities, given your
description of the study. For example, the subject might have been
controlling for having the light on, regardless of the shock signalling
schedule. It would also have been nice if you had tried a number of
different disturbances to determine that it was, indeed, the signalling
schedule that was under control.

Apparently I was doing PCT research (testing for the controlled variable)
as far back as 1973, when this study began. (;->

You were, indeed. And now that you are familiar with PCT I bet you can
think of far better ways to find out what the subject is controlling in this
rather unpleasant (for the rat) situation.



<[Bill Leach 950602.00:56 U.S. Eastern Time Zone]

[From Bruce Abbott (950601.1635 EST)]

I should be in bed (and you probably wish that I was) :slight_smile:


No I don't think that mine are suffering too badly. I don't take any of
this personally and fully agree that "coming to terms" is anything but an
easy task. The really important thing here is that everone honestly make
an effort to understand what the other is saying.

Sometimes the "what I was trying to discuss was..." is indeed helpful
even though "the other point" may be important too.


Did the rats ever press the lever during the signaled condition? If so
then what does that mean?

I personally have quite a bit of trouble with this sort of experiment in
that I believe that the whole setup is contrived. The rats were
essentially placed into a situation that would never exist in their
"normal" environment.

Typical behaviour for an animal experiencing a shock is, as far as I have
observed, to leave the place where the shock occurred and if possible
never return.

It seems to me that attempting to learn what the controlled variables are
for "typically normal" behaviour would be the initial goal of PCT
research. Next would likely come studies of frequently observed
"abnormal" behaviour and then maybe studies of behavioural situations
that the subject would not normally ever encounter.

I will accept "flak" for this from Bill P. and Rick on this but it seems
to me that asserting that "signaled schedule in effect" is just assigning
the observers understanding of the experimental apparatus to the rat.

In other words, I suppose that I am looking for something more basic
though I admit that even learning that the rats could learn to do this is
more than just a bit of a surprise to me.

You did not mention if there was a way for the rat to avoid the shock if
the light signaled its impending arrival.

Apparently I was doing PCT research (testing for the controlled
variable) as far back as 1973, when this study began. (;->

Better minds than I might be able to tell me what is wrong with this but
somehow I don't see this as testing for the controlled variable. My
difficulty might of course be with trying to think in terms of testing
methods for a logical variable.

I easily see (in principle) how one tests for a CEV that is controlled to
a fixed reference or even one that varies (if some idea exists as to why
it would be varied). In that case all one really has to do is attempt to
change the (predicted) CEV and measure what the subject does (recognizing
of course that the actual task is a bit more difficult since the subject
may change the reference based upon other perceptual input - such as
noticing that you are doing something).

BTW, the title sounds anything but PCT! :slight_smile:


<[Bill Leach 950602.02:09 U.S. Eastern Time Zone]

[From Rick Marken (950601.1900)]

Bruce Abbott (950601.1635 EST) --


Yes. I agree, your experiment definitely involves the Test. ...

Ok, so I got my flak even before you saw my message! :frowning: