[From Bill Powers (970816.1007 MDT)]
Bruce Abbott (970816.0900 EST)--
I give Skinner credit for sticking to observables, but not for his _a
priori_ assumption that the environment had to be the determinant of
behavior...
Obviously, but Skinner wanted to avoid speculating about the inner
organization of the organism, because this type of speculation had already
established a very bad track record in psychology. One could always invent
just the right inner organization to explain the data at hand ...
Skinner was quite right in criticizing the "intervening variable" theories,
those which explained behaviors using Bateson's "Dormitive Principle"
(sleeping powders make you sleepy because they contain a Dormitive
Principle). But that kind of theory is not a system analysis or a system
model. What Skinner should have been criticizing was the lack of
understanding in psychology of the way more successful sciences make
models. But he couldn't do that, because he didn't know how to make models,
either.
-- and people
were expending a lot of effort devising and carrying out tests to
discriminate different proposals, often with ambiguous results. Better to
carry out a systematic series of well-controlled empirical investigations --
the empirical relationships thus discovered would have lasting value; they
would be the phenomena that any competent theory of inner organization would
have to explain.
You are really idealizing Skinner's practices, or else describing what he
advocated rather than what he did. I admire his cleverness, but not his
ability to think up critical experiments. He was much too ready to
compartmentalize his thinking, so that for example he could demonstrate how
reducing the reinforcement rate could drive an animal to greater and
greater behavior rates -- without ever noticing that in this case,
_reducing_ reinforcement was _increasing_ behavior. Skinner never seemed to
understand that a general principle is supposed to be _general_ -- apply
all the time, not just when you want it to or when it happens to fit what
you see. If an increment of reinforcement is supposed to produce an
increment in behavior, it must do this EVERY TIME, even when you're not
focusing on that aspect of the experiment. If it doesn't, it's not a
general principle.
In reinforcement theory, the reinforcement phenomenon is simply a given, an
empirical fact. No attempt is made to explain why, under given conditions,
a given consequence of behavior will sustain that behavior.
And that, my friend, is the old red flag again. The consequence is not what
sustains behavior. Listen to your own advice. It is _the existence of the
relationship_ , plus the organism's continued need for the consequence,
that sustains the behavior. Every time you hint that somehow the food
pellets are doing something to the behavior, like "sustaining" it, I'm
going to blow the whistle. Right in your ear. Maybe this will condition you
to stop saying such things.
Maybe so, but I thought that by making clear what I _meant_ when I say such
things, you would grant me the license to use this more compact way of
speaking, rather than insisting that I have drifted back to meaning what
_you_ insist that I mean.
What I want to do, Bruce, is deprive you of the use of language that
permits you to assert environmental causation, whether you intend this to
be the meaning or not. Since I can't do that, I am trying to persuade you
to give it up voluntarily, one day at a time. This isn't just a "compact
way of speaking" -- it's a way of getting two messages across at the same
time, one overt and one covert. The overt meaning, the one you will admit
to, is the whole situation in which providing a contingency results in an
animal using it for control of something it wants. The covert meaning is
that the thing it controls is really controlling _it_. All you have to do
is to read the literature of EAB to know that this covert message is
explicitly intended by most workers. Why encourage this view? Why create
the appearance that you support it?
When I speak of a given consequence of behavior
sustaining that behavior, I'm talking about the role of the contingency in
keeping the behavior going. I am not asserting that the consequence exerts
some magical force to propel the behavior.
Then choose your words carefully so you don't give the impression that some
variable involved in behavior is keeping the behavior going. What keeps the
variable going? The behavior! Skinner wanted to treat a dependent variable
as if it were an independent variable; you can't get away with that among
engineers, or in many other quarters.
In the first sentence above you say first that a _consequence_ of behavior
sustains the behavior, and immediately afterward, in the same sentence,
that it is the _contingency_ that keeps the behavior going. The contingency
is not a consequence of behavior; it's a property of the environment lying
between the behavior and its consequences. You're using these terms in a
loose free-associative way. If you mean contingency, which is a function
making one variable depend on another, say contingency. If you mean
consequence, which is a variable that is a function of another variable,
say consequence. The clarity of your thinking is reflected in the clarity
of your language. If you use muddled language, your thinking is muddled,
too. And even if you manage to keep clear thinking going despite the
muddled language, your communication gets muddled whether you know it or not.
In a gasoline engine, the
gasoline sustains the engine's running. But so does the spark, and the air
being pulled into the cylinders, and the energy stored in the flywheel.
Remove any one of those things and the engine quits. When I speak of
"sustaining" behavior, I'm talking about the conditions necessary in order
to maintain its performance.
There is a difference between necessary and sufficient. It is necessary for
behavior to be able to affect consequences if there is to be any change in
behavior, but it is not _sufficient_ for behavior to affect consequences.
Many other variables and functions of equal importance are involved, no one
of which is sufficient, but each one of which is necessary. We are not
talking about lineal causation here; we're talking about a circle of
causation, a closed loop in which all the parts play a role in determining
the outcome, but no one part plays a determining role. A consequence of
behavior is merely one link in a closed loop of variables which are
successive functions of previous variables in the loop, all the way around
it. Ultimately, a consequence of behavior, if controlled, is a function of
itself. Every variable in the loop is a function of itself. The only
independent variables are disturbances and reference signals.
Yes, there other necessary conditions besides
the provision of some particular consequence of the behavior;
Again, muddled language. Are you talking about the _provision_ that makes
the consequence a function of behavior (the contingency)? Or are you
talking about the _consequence_ that is provided by the behavior? WHAT
provides the particular consequence of the behavior, and what do you mean
by "particular?" It is the behavior that provides the particular _amount_
of the consequence; it is the contingency that provides a particular _kind_
of consequence. The experimenter setting up the contingency has no way to
determine how much of a consequence will appear; only what kind. It is the
organism's behavior that, given the contingency, determines how much (if
any) of the consequence will appear. By leaving out the provider of the
consequence, you make it appear that the consequence just appears, like an
independent variable. But for the phenomenon you're talking about to exist,
it is _essential_ that it be the behavior that provides the consequence,
not some independent unnamed agency.
This subjectless construction is a way of concealing the fact that it is
the organism that produces a particular amount of consequence. To
acknowledge that cause of the consequence explicitly would weaken the idea
that the consequence has some causal role in shaping behavior. Therefore,
the propagandist hides the agent by skipping over it in the sentence, as if
it made no difference what produced the reinforcer.
It would be nice if we could discuss the
issue with this understanding rather than insisting that I mean something
else and arguing on that basis.
I refuse. Say what you mean, explicitly and precisely. Why should I always
have to be clarifying and translating your language for myself? If you
insist on continuing to use your "compact" language, it can only be because
you _want_ to get the covert message across -- you want to leave an opening
for an interpretation that puts causation into the environment. You want to
sound like a behaviorist. Come on, Bruce; what's wrong with clarity and
precision?
···
-------------------------
Let's try to take this a step at a time. I'll take the prototypical example
of a rat pressing a lever for food pellets. The rat has been deprived of
food for a time and has previously learned that it can obtain food by
pressing a lever, whereby the apparatus delivers a food pellet, and then
consuming the pellet.
We start this particular session with the contingency in effect (presses
produce food.) We observe that under these conditions (food deprivation
plus contingency), the behavior (lever pressing-food consumption) is
maintained, i.e., we observe the rat repeatedly press the lever and consume
the food, press the lever and consume the food, press the lever and consume
the food.
To say that the behavior "is maintained" is not the same as explicitly
saying that the _rat_ maintains its behavior, and thus maintains the food
intake. This passive construction leaves open the way to speculate about
WHAT is doing the maintaining. But the maintenance is not done by anything
outside the loop: the whole process _maintains itself_.
Now break the contingency by disconnecting the feeder, so that pressing the
lever no longer produces a food pellet. After a time, we observe that the
rat is no longer pressing the lever at the high rate that had formerly
characterized its performance. In fact, it rarely presses the lever at all.
Now we establish the contingency again, and in short order we find the rat
pressing and eating, pressing and eating, as before.
_By definition_, the food pellet is a reinforcer. When the pellet is
produced by pressing the lever, pressing the lever occurs at a high rate.
When the pellet is not produced by the lever, pressing the lever is not
maintained. We might call this EAB's Test for the reinforcer.
I'm beginning to think that your problem is simply one of ambiguous
thinking, and it shows in your language. Your concepts are fuzzy. "When the
pellet is produced by pressing the lever" could mean either "when a pellet
appears because of a lever press" (emphasis on the appearance of a pellet)
or "when it is possible that a lever press might produce a pellet"
(emphasis on the existence of the contingency). Likewise, "When the pellet
is not produced by the lever" could mean "When pressing the lever produces
no pellet," or "when there is no press that produces a pellet," or "when it
is not possible that pressing the lever could produce a pellet." Your words
and constructions do not pin you down to a single meaning, which indicates
to me that the underlying concepts are not clearly distinguished in your
mind. I don't think you have clearly distinguished, in your own thinking,
between the appearance of a food pellet (the reinforcer) and the
relationship that gives behavior the ability to produce a food pellet (the
contingency). You don't seem able to make up your mind whether it is the
occurrance of the reinforcer that accounts for the increased behavior rate,
or the existence of the contingency.
You could equally well interrupt the loop at any other point and define any
other variable as the reinforcer. For example, you could inject curare into
the muscles to prevent bar-pressing. No muscle contractions, no behavior;
muscle contraction, behavior -- but only if the loop is closed. So the
muscle contractions are reinforcers. Or you could cut off sensory access to
the food pellets; same result: sensory responses are reinforcers -- if the
loop is closed. Heck, you could clamp some variable in the middle of the
program that generates the contingency to zero, and show that that variable
is a reinforcer. The whole loop is made of nothing but reinforcers!
Can PCT explain why the food pellet acts as a reinforcer? Bill Powers says
no. I say yes. The food deprivation prevents the rat from controlling its
daily food intake, which must be maintained because the food is the rat's
fuel and is being used up by metabolic processes. As a result, a controlled
variable (energy intake) is brought below its reference level. The rat has
learned that it can control the CV in the operant chamber by pressing the
lever in order to produce a food pellet and then consuming the pellet. The
pellet is able to increase the level of the CV (once the pellet is
swallowed) because it contains the necessary energy in the form of
digestable nutrients.
The food intake is not maintained "because the food is the rat's fuel." It
is maintained because there is a physical reference signal specifying a
nonzero level of food intake (some of the time) for the associated control
system (and, of course, because the rest of the control system is working).
And that reference signal is not maintained "because the food is the rat's
fuel." It is maintained because some other system is controlling stored or
circulating glucose and is experiencing an error. And that system does not
maintain the glucose level "because the food is the rat's fuel." It
maintains it because it receives a nonzero reference signal from still
another system perceiving and controlling effects that depend on blood
glucose level. And so forth. However far back you follow this trail, you
will never come to a control system that is acting "because the food is the
rat's fuel." That sort of idea is irrelevant to understanding how the rat
works, what it is controlling, or why it does what it does.
So, in the steady state, we get
lever pressing when lever pressing produces food, and we do not get lever
pressing when lever pressing does not produce food, the pair of outcomes
which together define the food as a reinforcer. We have explained why the
food is required in order to sustain lever pressing (is that better, Bill?
I almost wrote "why the food sustains lever pressing.")
See above discussion of what is a reinforcer. And no, it is not better. You
still leave out what is sustaining the lever pressing. What sustains the
lever pressing is a signal from the nervous system that depends both on
food intake and the reference signal setting. WHAT requires food "in order
to sustain lever pressing"? This damnable passive construction in which the
subject is quietly dropped out! It is the _RAT_, via reference signals,
that "requires" the food.
And we have
explained why, if we are to observe this outcome, it is necessary to deprive
the animal of food. And you say that PCT doesn't explain the reinforcement
phenomenon? I think I've just shown otherwise.
PCT explains the behavioral relationships, but it doesn't explain
reinforcement because there is no such thing. The food has no special
reinforcing effect; it has a nutritional effect, and that is all. Any
reinforcing effect is a product of the observer's imagination. I refuse to
attribute any effect to the food other than its effect as a source of
energy and building materials. Those are the ONLY effects we need to
consider to apply the PCT model.
I agree that the manipulations you describe above can easily give the
impression that the food is doing something in addition to providing
nutrition. That, indeed, is the whole thrust of your argument. If you let
behavior produce food, you get behavior; if you don't, you don't get
behavior. What could be more reasonable than to conclude that the food is
what determines the presence or absence of behavior? But this naive
conclusion focusses down on just one variable in the loop, and overlooks
the fact that you could say exactly the same thing about ANY variable. The
role you are calling "reinforcer" could be assigned to any variable in of
the loop, as could the role you call a "contingency" (to any function in
the loop).
What you're doing is known as synecdoche -- "a figure of speech in which a
part is put for the whole, as in 50 sail meaning 50 ships." In this case,
you are giving a part a function which is a property of the whole loop, a
part that you happen to be able to see and consider important.
I don't know about this discussion, Bruce. I find myself giving you lessons
in how to speak and think, lessons to which I very much doubt that you are
paying any attention. You have your way of talking about things, and it
doesn't seem that anything can influence that or lead you to wonder if
these ideas are really as clear as you believe they are.
Best,
Bill P.