Underlying Factors

Underlying Factors

Psychologists have long studied the factors that are necessary and sufficient
for producing classical conditioning. One important principle is contiguity,
which refers to events occurring closely together in space or time. Classical
conditioning is most effective when the CS and US are contiguous, though
precisely how closely together they must be presented depends upon the
type of classical conditioning observed. Taste aversion conditioning, for example,
will occur over much longer CS-US intervals than would be effective
with other conditioning arrangements. Nevertheless, the sooner illness
(US) follows taste (CS), the stronger the aversion (CR) will be.
Though seemingly necessary for classical conditioning, contiguity is not
sufficient. A particularly clear demonstration of this fact is seen when the CS
and US are presented at the exact same moment (a procedure called simultaneous
conditioning). Though maximally contiguous, simultaneous conditioning
is an extremely poor method for producing a CR. Furthermore, the
order of presentation matters. If the US is presented before the CS, rather
than afterward as is usually the case, then inhibitory conditioning will occur.

Inhibitory conditioning is seen in experiments in which behavior can
change in two directions. For example, with a conditioned suppression procedure,
inhibitory conditioning is seen when the animal increases, rather
than decreases, its ongoing behavior when the CS is presented.
These findings have led modern researchers to focus on the predictive relationship
between the CS and the UCS in classical conditioning. An especially
successful modern theory of classical conditioning, the Rescorla-
Wagner Model, suggests that CS’s acquire associative strength in direct proportion
to how much information they provide about the upcoming US. In
addition to providing a quantitative description of the way in which CRs are
learned, the Rescorla-Wagner model has predicted a number of counterintuitive
conditioning phenomena, such as blocking and overshadowing.
Taken as a whole, the newer theoretical conceptions of classical conditioning
tend to view the learning organism less as a passive recipient of environmental
events than as an active analyzer of information.


Does classical conditioning account for any human behaviors? At first
glance, these processes might seem a bit simplistic to account for human behaviors.
However, some common human reactions are quite obviously the
result of conditioning. For instance, nearly everyone who has had a cavity
filled will cringe at the sound of a dentist’s drill, because the sound of the
drill (CS) has been paired in the past with the unpleasant experience of having
one’s teeth drilled (US). Cringing at the sound of the drill would be a
conditioned response (CR). Psychologists have found evidence implicating
classical conditioning in a variety of important human behaviors, from the
emotional effects of advertising to the functioning of the immune system to
the development of tolerance in drug addiction.