Logan:  Basic Principles of Learning

                  PRINCIPLE: SECONDARY MOTIVATION -- FEAR

          If an originally neutral stimulus is more-or-less regularly 
          paired with an aversive state of affairs, that stimulus
          will acquire motivating properties.

     Secondary motivation is an instance of classical conditioning since 
it involves the pairing of an antecedent stimulus with a US.  In classical
conditioning we typically observe some overt response that is similar to 
the UR whereas in the present context, we are interested in whether the
originally neutral stimulus had acquired motivating properties as revealed 
in two ways: (1) the stimulus should serve to energize or potentiate 
behavior and (2) the termination of the stimulus should serve as negative
reinforcement.  We know that electric shock will motivate an organism
into various kinds of behavior and that the termination of shock will increase 
the likelihood of an escape response.  We are now saying that a stimulus 
such as a light or a tone that had previously preceded the onset of 
electric shock will display these same properties.

     One demonstration of the principle involves first placing a rat in a
distinctive box in which it receives unavoidable and inescapable shocks.  
After this has been done a number of times, the rat is placed in the box 
and a door is opened that permits the rat to leave that box and go into 
another box that is distinctively different.  Rats will not only learn to 
leave to make another instrumental response such as pressing on a bar, in 
order to open the door leading into the safe box.  It is inferred that the 
shock box has acquired motivating properties from the activation of trial-
and-error behavior an the reinforcing effect of getting out of that box.

     An important factor determining the secondary motivational
properties acquired by an initially neutral stimulus is the intensity of
the aversive event encountered during conditioning: the strength of
conditioned fear is greater the more intense the aversive stimulus.

     It is important to note that, in this experimental demonstration no 
shock is given during the second (learning) phase.  Were shock still to
be given in the original box, escape learning could be attributed to primary
negative reinforcement.  In order to preclude that interpretation of the
findings displayed in the figure, it is necessary to eliminate shock from 
the situation entirely which means, of course, that some extinction of
conditioned fear is inherent in the procedure.  It is for this reason that 
the curves in the figure show a decrease, although it should be noted
that conditioned fears, especially when based on intense aversive
stimuli, are extremely persistent.  A rat might run hundreds of times out
of a box in which it had received only a few very intense shocks.

     Another procedure used to study secondary motivation is called the
CONDITIONED EMOTIONAL RESPONSE (CER).  The organism is first trained to 
emit an operant response on a VI reinforcement schedule.  Then superimposed 
on this baseline behavior is a warning signal preceding by several seconds 
an unavoidable electric shock.  After a few such pairings, the operant 
behavior is suppressed during the warning signal.  This is often called
"conditioned suppression" and can be interpreted to mean that the warning 
signal acquires motivating (fear arousing) properties, and that fear is 
somehow incompatible with the operant performance.  In similar fashion, 
if bad news arrives just before dinner, you are likely not to eat very much.

     Insofar as is known, all of the principles of classical conditioning 
also apply in the context of secondary motivation.  Specifically, 
conditioned fears increase with the number of times the stimulus has been
paired with an aversive event, and are related to the interstimulus
interval.  This latter effect is more apparent in a situation in which
the shock is neither avoidable nor escapable during original conditioning.
Subsequently with shock no longer employed, the rat will learn to press a
bar to turn off the tone each times it comes on.  In this case, optimal
fear conditioning as displayed by the learning of the instrumental
response occurs if the tone initially preceded the shock by about one
second.

     Although a Utopian environment might conceivably be totally devoid
of aversive events, real life is never so tender and kind.  Fortunately,
most of these we can avoid or be prepared to escape quickly in which
case, although  fear conditioning is presumably implicated, the threat is
real.  The power of this principle is more evident in the case of
unrealistic fears that may have been real enough when acquired but which
are no longer threatening.  For example a small child's fear of a
tyrannical parent is well founded at the time but may continue to haunt
the adult when a confrontation would be more evenly matched.  More
generally, we all tend to overreact to words, which after all, are only
marks on a page or sounds in the air and therefore harmless in their own
right but which may refer to fearful things.  This is especially true of
common "four-letter" words.

TERMS: Secondary drive, fear, secondary motivation, conditioned emotional
response, conditioned suppression