the process by which we learn to give a certain response to a particular stimulus. I had two cats who always came running whenever they heard the electric can opener. Even though we used the opener for all sorts of cans, at least once every day we used it to open their food, so they became conditioned to run to the kitchen when they heard it. There are actually two kinds of conditioning: (1) Classical conditioning, as discovered by Ivan Pavlov, established that a certain stimulus causes a specific response. This is what my cats were subject to. (2) Operant conditioning, as discovered by Thorndike and tested by B. F. Skinner, says that we associate certain behaviors with the consequences they bring. Therefore, behaviors that are reinforced will increase, and those that are punished will decrease.