Describe the basic principles of classical conditioning

The basic principle of classical conditioning is the idea
that a subject can be taught an "unnatural" behavior through repetition.  Typically, in
classical conditioning, a subject is taught to act in a given way when exposed to a
neutral stimulus that would not usually make the subject act in that
way.

The classic example of this is the experiment done by
Ivan Pavlov with his dogs.  This is the experiment from which we get the term "Pavlovian
response."  In this experiment, the gods were taught to act in a given way (to salivate)
when they were exposed to a stimulus (the bell) that would not usually have made them
salivate.

The principle behind this is that subjects can be
made (through reptetition) to respond reflexively to a stimulus that ought not to cause
that particular reaction.