what is classical conditioning?

This is when a person gives a conditioned response after association a conditioned stimulus with a neutral stimulus. An example of this can be seen in Pavlov's theory with the example of the dog salivating when it sees food.The unconditioned stimulus is food and it leads to the unconditioned response of salivation When a neutral stimulus such as a whistle is repeatedly paired with the unconditioned stimulus of food, eventually the neutral stimulus becomes the conditioned stimulus. This means that even in the absence of food, the whistle leads to the conditioned response of salivation. Here is a diagram that may help to better explain this