[From Bruce Abbott (981022.1125 EST)]
Bill Powers (981022.1322 MDT) --
Bruce Abbott (981022.0910 EST)
So I've been thinking about doing something more along the lines of a
tracking study, in which the rat would track the "target" simply by
following it with its body. Another possibility, more along the lines you
suggest, would be to provide some analog device with which the rat could
control the frequency of a tone.
These are great ideas. You can create a movable light source with a set of
32 or so LEDs powered by the digital outputs of your A/D board. If these
are arranged in a horizontal line, the rat could be asked to learn to keep
its nose tracking the moving light for some time before a food pellet was
delivered. This is a much more natural sort of task than repetitively
pressing a bar -- rats seem to lead with their noses all the time, by
moving their bodies around.
Shouldn't be too hard to build, although it would take a well thought-out
training program to teach the rat to perform the task.
One very useful and cheap analog device is a cadmium sulfide photocell. It
has a resistance that varies with light intensity (more light, lower
resistance). If you put it in series with a fixed resistor and apply a
voltage across the series pair, you get a voltage output that varies
continuously with changes in light intensity. You can easily arrange for
the rat to vary this voltage by moving its nose in and out of a circular
cutout above the photocell, blocking more or less light. The computer can
then convert the digital representation of the voltage into any other
physical effect you please, such as the tone you mention.
Funny you should mention the CdS cell -- years ago I hooked one up across
one axis of the joystick input of an IBM PC Jr. and wrote a BASIC program
that displayed a digital "meter" on the screen that displayed a number which
varied with the intensity of the light falling on the cell. The CdS cell is
one of the few components Radio Shack has kept in stock for years . . . I
imagine a rat would not have too much trouble learning to stick its nose in
the hole -- rats will investigate any opening by poking their noses into it.
It would probably require a two-stage training procedure to get the rat to
control a tone. In the first stage the rat would learn that food appears
only when the tone has a certain frequency. In the second state it would
learn that it can control the frequency by poking its nose into the hole and
adjusting the position.
Just my luck -- at the moment I'm absolutely ratless. (Don't you just hate
it when that happens?) I'll have to submit a protocol, have it approved,
construct the necessary apparatus, and obtain the rats before this can
happen. Given everything else I have to do this semester, that could take a
From Phil Runkel to Bruce Abbott again:
Ah, now I see that you were needing something for tracking. Well,
maybe I'll think of something useful next time around.
[From Rick Marken (941229.2045)]
The operant research you are planning with Bill will give us all an
opportunity to see whether rats are really controlled by food pellets or
whether they are controlling some perceptual characteristic of those
Bruce Abbott (941229.1530 EST)--
What, do you think there's any doubt?
I think there is a hugh amount of doubt. The entire operant behavior
"establishment" believes that consequences control behavior. All
operant research I know of is aimed at determining the relationship
between behavior and its consequences rather than determining what
consequences that organisms control. All models of operant
behavior (other than PCT models, of course) are designed to explain
_how_ consequences control behavior rather than how consequences
are controlled. The only published evidence I know of that rats control
perceptions in an "operant behavior" situation is Bill Powers' PCT
analysis of a "rat experiment" in Behavioral Science. So, yes, I do think
there is more than a little doubt that rats control the consequences of
did you [Bruce] always know that organisms were perceptual control
systems? If so, is your research methods text all about how to study
perceptual control systems?
Since you haven't answered this for me yet, and since I'm on vacation,
I took a pleasant walk over to UCLA and looked over your research
methods text myself. I'm afraid I was unable to find much in it about how
to study living control systems. I looked for "controlled variable" in
the index but didn't find it. Maybe you called it something else?
I did find quite a bit about how to determine the causes of behavior
by manipulating independent (environmental) variables and determining
whether or not they had a statistically significant effect on a dependent
(behavioral) variable. I even learned that I should be careful to
_control_ extraneous variables that might also have an effect on behavior.
But I didn't understand how I could do this controlling unless I
was lucky enough to be near an extraneous variable that would cause
me to do it;-)
Actually, the book reminds me of one I wrote in my deep, dark conventional
psychological past. My book was called "Methods in experimental psychology";
it was completed just about a year after I started to really understand
PCT. So I knew I was publishing BS -- but I had a higher level goal;
tenure; and I got it. If the book had done well enough to go into a
second edition I would have changed nothing except the title. The new
title would have been: "Statistical analysis of irrelevant side effects
of controlling". That would have assuaged my guilt even if it didn't
By the way, Bruce. What's your snail mail address; I've got a copy of
the "Blind men..." paper ready to go.