Logan:  Basic Principles of Learning

                PRINCIPLE: OPPONENT MOTIVATIONAL PROCESSES

          The termination of an emotionally-significant event is 
          followed by an opposite emotional state; with repeated 
          stimulation, there is a decrease in the original emotional 
          state and an increase in the strength and duration of the 
          opponent state.

     Our emotional lives, our "ups" and "downs," do not come and go 
abruptly from some middle-of-the-road neutral level.  Instead, the time 
course of our reactions to an emotionally-significant event (pleasant or
unpleasant) follows a rather complex pattern characterized by (1) a peak 
of emotional reaction, (2) a lower steady level for the duration of the
stimulus, (3) a reversal to the opposite emotional state after termination 
of the stimulus and finally (4) a gradual return to the normal level.  The 
the higher the emotional reaction to the event, the higher the opposing 
process after the stimulus has terminated.  The pattern is something like 
a pendulum that, after being displaced in one direction, swings back into 
the other direction.

     An early observation suggestive of this pattern was made by Pavlov in 
the context of differential conditioning.  He observed that, if S+ is 
presented soon after S-, the dog is likely to show an excessively strong
conditioned response.  He termed this phenomenon POSITIVE INDUCTION because 
his interpretation was that S- produced a strong inhibitory state but when 
it ended, there was a temporary super-excitatory state which would
increase responding to any positive stimulus.  Conversely, NEGATIVE
INDUCTION arises when an S- is presented shortly after an S+.  In this
case, the idea is that S+ leads to a highly excitatory state which, after
S+ ends, passes through a temporary inhibitory state that will further
depress the tendency to respond to S-.

     This temporary reversal is characteristic of many of our biological
systems.  For example, a negative after-image (dark spots) after looking at 
a bright light is a familiar experience.  You may have enjoyed the
childhood activity of spinning around in one direction, and then standing
still while having the sensation of spinning in the other direction.  In
contrast to these sensory experiences, the opponent motivational
processes have a unique and very important property: Frequent exposure
decreases the primary process and increases both the intensity and
duration of the opponent process.  The nature of the effect can most
readily be appreciated by consideration of drug-taking behavior, say
marijuana.  For the first few exposures, the experience while smoking pot
is a "rush" or heightened state of euphoria.  The opponent process after
the joint is finished, is one of desire for more, which fairly rapidly
recovers to the normal resting state.  The veteran user, however, the
addict, experiences only a moderate state of contentment during 
the smoking episode, which is followed by an agony of withdrawal and a 
prolonged period of craving.    

     It must be emphasized that the primary process can as well be 
emotionally negative, resulting in a positive opponent motivational state.  
For example, during the first efforts at jogging, the experience is one
of moderate pain and discomfort, followed by a pleasant state of relaxation.  
With repeated experiences, however, the primary reaction when jogging is 
less negative, may almost be exciting, but it is followed by a prolonged 
happy feeling of exhilaration.  In sum, we can indeed become trapped into
engaging in behaviors that are basically aversive because it makes us feel 
so good to stop.

     Functionally, opponent motivational processes provide a form of 
positive feedback.  Feedback is said to be positive when it naturally 
leads to further performance of the behavior producing the feedback, which 
is contrasted with negative feedback that tends to terminate the
behavior.  Consider the behavior of eating.  Normally, the primary
feedback effect is to a decreased desire for food.  However, the opponent
motivational process adds a source of positive feedback because, one you
begin to eat, each time you start to stop eating there is an aroused
craving to continue eating.  In effect, you may soon be eating just to be
eating, a fact that you can readily convince yourself of by deliberately
stopping eating sooner than usual and observing your own feelings.  For a
very few minutes, you will continue to want to eat, but once the opponent
motivational process has run its course, you will find that you really
aren't hungry.

     The inclusion of the Principle of Opponent Motivational Processes may 
be somewhat premature.  In contrast to the other principles described in 
this book, which have enjoyed at least a quarter-century, and typically a 
half-century of refining experimental analysis, the present principle is 
a relative newcomer to the scene.  I chose to include it, however, to 
emphasize that the principles are not completely static or "written in 
stone".  Our perception of them is continually being revised, and new ones 
are continually vying for recognition.  And in this case, the potential
practical significance of the principle justifies early presentation.  One 
of the distressing statistics of modern society is the frequency of
suicide, especially among college students.  The facts are that few of
these young people really want to die, but they have been overwhelmed by
some apparent devastating emotional experience.  The Principle of
Opponent Motivational Processes implies the familiar saying that every
dark cloud has a silver lining.  Anything you can do to help yourself or
a despondent friend weather the depths or despair will be repaid
handsomely when the pendulum swings.

TERMS: Opponent motivation process, feedback (negative, positive).