Confusing Consequences:
A Brief Introduction to Operant Conditioning
I originally crossposted this to the Obed-Comp-L
(Obedience Competition Mailing list) and Click-L (a list for those interested
in Karen Pryor's point of view) in the summer of '95.
I have found that many people confuse
negative reinforcement and punishment. These people include dog trainers,
college students, and surprisingly, even many college professors and
Introduction to Psychology textbooks. In fact, I recently read the book Don't Shoot the Dog! by
Karen Pryor and was a bit dismayed to find this confusion there as well. Note
that this is not an attempt to flame the book or criticize it unduly. I like
the book and learned a lot from it. I recommend it highly to anyone interested
in training animals (and sometimes even those interested in training their
children). Nonetheless, I do believe that the book suffers from the problem of
confusing negative reinforcement and punishment. As such it propagates this
confusion because many dog trainers look to this book as a definitive source on
the science of behavior.
I should note, however, that in the
preface to the book Karen Pryor says (p.16), "Before going any further, I
must apologize to any professional behaviorists who
are annoyed at my cavalier uses of the vocabulary of reinforcement theory. . .
. hair splitting definitions have proliferated. So I
have sacrificed technical precision for a vocabulary I think people can
understand." While I don't consider myself a professional behaviorist and I wouldn't say I was annoyed, I do believe
that clearing up this confusion will lead to a more wise and productive use of
the principles of operant conditioning.
Therefore, I'd like make an attempt at
clearing up the confusion over negative reinforcement and punishment. Both are
considered consequences of behavior and the notion of
the consequences of behavior is central to operant
conditioning. The basic paradigm of operant conditioning is that:
|
R -----> S* |
|
Which should be read as: |
|
a Response
(leads to) a Stimulus consequence |
For
example, when the dog sits, (s)he gets a cookie. Note
that there exists a contingency between the R and
the S*. This means that whether the S* is
administered depends upon the occurrence of the R. In
other words, the dog will only get the cookie if, and when, it sits.
Keep
in mind that things are a bit more complicated. An S* can
also be contingent on No R. Thus, there may be a
consequence of not responding. For example, if you don't smoke I'll give you a
cookie. Things are also complicated by the fact that a Discriminative
Stimulus (or S-D) usually signals that a particular
contingency is in effect. For example, I tell the dog to "Sit". What
this really tells the dog, is that if it puts its butt on the floor right now, it will get a smile (and maybe even a cookie).
I
believe the confusion over negative reinforcement and punishment is due to
several factors. The first concerns the term "negative". It suggests
something bad or unpleasant. From a scientific perspective, however, the terms
positive and negative are used in a mathematical sense. Positive refers to
addition and negative to subtraction. In the case of the consequences of behavior, positive refers to the adding or giving of
something and negative refers to subtraction or taking something away. Let me
elaborate on this reason for the confusion before going on to discuss others.
Basically,
there are two kinds of events: pleasant and aversive. An example of a pleasant
event is food and an example of an aversive event is electric shock. These
events can be viewed as primary (related to a biological need) or secondary
(previously paired with a primary). Furthermore, an event can
be given (positive) or taken away (negative). Thus, there are four
possible stimulus consequences of behavior or S*'s.
|
|
What
you do with the event |
|
|
Type
of event |
Give
it |
Take
it away |
|
Pleasant |
||
|
Aversive |
||
It is
important to note that the goal of reinforcement is to increase the
likelihood of the behavior in the future, while the
goal of punishment is to decrease the likelihood of the behavior in the future. Note also that from this point of
view, the terms 'negative' and 'aversive' have very different meanings.
In an
effort to make this material as clear as possible, I would like to give a
formal definition and an example for each of these four consequences.
Definition: The
giving of a pleasant event contingent on a behavior
with the goal of increasing the likelihood of the behavior
in the future.
Example: Dog sits (or does whatever else you
might ask) and you give him/her food, play, and/or praise.
Definition: The
giving of an aversive event contingent on a behavior
with the goal of decreasing the likelihood of the behavior
in the future.
Example: Dog sits up on the long down in the
AKC obedience exercise and the owner becomes verbally and/or physically firm.
Definition: The
removal of an aversive event contingent on a behavior
with the goal of increasing the likelihood of the behavior
in the future.
Example: A technique for teaching the retrieve
involves releasing an ear pinch or terminating a shock at the moment the dog
clasps the dumbbell in its mouth.
Definition: The
removal of a pleasant event contingent on a behavior
with the goal of decreasing the likelihood of the behavior
in the future.
Example: Puppies learn bite inhibition during
play when we recoil and cease playing for a moment or two when the dog is too
rough. Also, consider the earliest stages of teaching a dog to heel. We may
give constant praise and encouragement when the desired behavior
occurs but we will withhold the praise when the behavior
observed does not meet our criteria of "good heeling".
I
believe that a second reason for the confusion of negative reinforcement and
punishment (which is very related to the first reason)
is the use of a popular slogan by the behaviorists --
"Accentuate the Positive". In light of the information I have
presented above, this slogan would be more accurate if it read --
"Accentuate the Use of Positive Reinforcement". The problem, however,
is that this latter phrase is not as simple or as catchy as the former.
A
final reason for the confusion of negative reinforcement and punishment is the
fact that they are interrelated. In order to use negative reinforcement, one
must typically administer the aversive stimulus in order to be able to
terminate it. For example, let us again consider the retrieve. An ear pinch or
shock is terminated at the moment the dog clasps the dumbbell in its mouth. In
order to terminate the aversive stimulus, however, it had to have been
initiated (i.e., administered) at some point. Thus, in order to use negative
reinforcement, one must typically employ positive punishment as well.
There
is a companion article available entitled Punishment: Problems & Principles for Effective Use.
Copyright ©
1996-99, Marty Plonsky, Ph.D. mplonsky@uwsp.edu. All
rights reserved. Please view his site Dr. P’s Dog Training.