How does classical conditioning demonstrate learning by association?

Classical conditioning demonstrates learning by association as one stimulus signifies the possibility of the occurrence of another stimulus. Unconditioned stimulus and response are gradually conditioned. For example, in the experiment conducted by Ivan P. Pavlov on the dog, a bell was rung after which food was served to the dog. After some days, no food was served after the ringing of bell, but the dog still salivated to the sound of it and thus, associated the bell with the food. The association resulted in the acquisition of the new response by the dog, i.e. salivation to the sound of bell. In this case, the bell was a conditioned stimulus and saliva secretion was a conditioned response.

Therefore, in classical conditioning, one stimulus signifies the possible occurrence of another stimulus.