Classical Conditioning by Ivan Petrovich Pavlov

The voluntary behavior of an organism with the present of reinforcement.

Before conditioning:

1.       The subject (a dog) is given food (unconditioned stimulus) and it reacts to produce saliva (unconditioned response).
  

2.      The dog is then introduced to a neutral stimulus (tuning fork) and it reacts nothing.
 

During conditioning:

3.       The tuning fork is present together with the food and they make the dog to produce saliva.
 During this phase, the tuning fork has been paired with the food.

After conditioning:

4.       The tuning fork is then being present alone without the food.
 Surprisingly, it managed to make the dog to response by producing saliva, and this time the response is called conditioned response.
 The tuning fork is then recognized as a conditioned stimulus.