Logan:  Principles of Learning

                 PRINCIPLE: PRIMARY POSITIVE REINFORCEMENT

          When a response is shortly followed by the onset of a stimulus 
          event that is innately emotionally positive, there is a greater    
          likelihood that that response will recur on future exposures to 
          the situation.

     This principle was first stated by Thorndike as the Law of Effect.
His analysis was that when an organism's goal-directed behavior is for
some reason blocked, the organism engages in random trial-and-error
behavior until some response is successful in attaining the goal.  The
occurrence of the goal event thereupon "stamps in" that response.  There
are two contexts in which the Principle of Primary Positive Reinforcement
is studied.  In INSTRUMENTAL CONDITIONING, the situation only arises or
the response is only enabled on discrete occasions (trials).  In this
case, response strength can be measured by the time after the response is
enabled before it occurs (response latency), or its speed or vigor.  In
OPERANT CONDITIONING, the response of interest is freely available
although it may not always be reinforced.  In this case, the probability
of the response can be measured by the rate at which the response is
emitted, which is conventionally cumulated over time 

     The Principle of Positive Reinforcement does not state that the
reinforcement must actually be produced by the response.  All that
is necessary is that a reinforcer shortly follow the response.  The Law
of Effect is therefore not so much in the effect of a response in
attaining reinforcement as in the effect of reinforcement in promoting
the future occurrence of the response.  Indeed, SUPERSTITIOUS BEHAVIOR
has been observed in animals to whom reinforcers are given without regard
to their behavior.  Reinforcement automatically tends to make the
organism repeat whatever was being done at the time, and if additonal
reinforcers happen to follow that same behavior, the organism becomes
seduced into performing it just as surely as if it were really producing
the reinforcement.

     In spite of superstitious behavior, there are some theorists who
contend that a person must be aware of at least the temporal relationship
between a response and reinforcement in order for there to be an effect.
The role of awareness in conditioning remains controversial, largely
because of the difficulty of objectively recording a subjective experience.

     A critical problem in applying the Principle of Primary Positive
Reinforcement is determining what kinds of stimulus events are innately
emotionally positive to the organism.  There is no agree-upon solution to
this problem.  It is generally recognized that substances that are
necessary for survival, such as food, water, and in a larger sense, sex
objects, qualify as primary reinforcers.  This is referred to as the WEAK
NEED REDUCTION HYPOTHESIS: Any event that reduces an organism's basic
biological needs is a primary reinforcer, but not all primary reinforcers
necessarily have this property.  For example, organisms are reinforced by
the sweet taste of non-nutritive saccharine.  We know this because
saccharine functions as a reinforcer -- Responses preceding the ingestion
of saccharin show an increased likelihood of recurrence.  In practice, we
often use the Principle of Primary Positive Reinforcement to determine
which stimulus events are reinforcing to the organism, and then use those
reinforcers further to control the behavior of that or similar organisms.

     In practical situation, we can successfully identify reinforcers as
stimuli that permit a person to do what he or she wants to do.  This is
referred to as the PREPOTENT RESPONSE HYPOTHESIS and it is indifferent as
to why a person wants to engage in the behavior.  Thus, if for some
reason a child likes to bang a stick on the table, you can reinforce less
interesting behavior such as studying the multiplication tables by
letting the child bang on the table after a period of studying.

     Of course, everyone knows that we tend to do things that are
followed by pleasant consequences, but few people know how to use this
principle to best advantage.  We shall encounter many illustrations in
the context of other principles of learning but let us begin to face up
to the matter of self-control.  We each know full well the kinds of
events that we personally find pleasurable; we also know the kinds of
behaviors that make us respected, responsible members of society.  One
readily available way to induce ourselves to engage in the latter
desirable behaviors is to make the former example, treat yourself to a
candy bar not before or while you are studying, but after you have
completed your assignment.  Appropriate self-reinforcement is an
important aspect of self-control.

TERMS: Conditioning (instrumental, operant), successive contrast,
hypothesis (drive reduction, prepotent response, weak need reduction),
Law of Effect, reinforcement (positive, primary), superstition.