Or, 
Extinction — In 
classical conditioning, a form of 
internal inhibition, in which the positive 
conditioned stimulus is temporarily transformed into a negative or 
inhibitory response, by the simple method of repeating it several times in succession without reinforcement.
Example:
  -  Dog is conditioned to associate bell with food.
  
-  Dog salivates at bell
  
-  This happens a few times, but no food arrives.
  
-  Dog stops salivating when the bell rings.
 
. . .
spit-balling...
. . . . . . .
Expectation and Disappointment 
Expectation:
An association has been taught. That is, a conditioned response (
CR) has been produced in the learner. When the conditioned stimulus appears, there is an 
expectation that the unconditioned stimulus (
US, usually something rewarding) is about to occur. In an 
ANN one should be able to produce a signal that represents expectation. That is, after the 
CS occurs and before the 
UR occurs.  In Netlab, this signal can even be set to increase with the passage of time sans 
UR.
Expectation unmet: (disappointment?)
If the expectation is not met after a certain amount of time passes, a disappointment signal should begin to ramp up. 
Disappointment may be a bad name for this phase, since, if the 
US is noxious (i.e., 
conditioned avoidance), the response will not be disappointment (relief? hopefulness? joy?).
Expectation:
        reward: anticipation, hopefulness,
        punish: apprehension, wariness,
Expectation Unmet:
        reward: disappointment
        punish: apprehension, disarray, hopefulness, 
. . . . . . .
Sources &; Resources