Classical conditioning means to associate two stimuli which each other. The most famous example is Pavlov’s dog; in the early 20th century, Ivan Pavlov trained dogs by presenting them a sound, followed by food (3). The dogs learned this association, and after a while, the dog reacted to the sound by producing saliva (4). They learned that the sound predicts food, and their body prepared for the expected food to come. If you want to read more, you can find more details here!

Operant conditioning means to associate one own’s action with a consequence. The most famous example is the Skinner box: B.F. Skinner trained rats in a box to press a lever in order to obtain food. In difference to Pavlov’s dog, here the animal learned that its own action (pressing a lever) is followed by a reward – therefore it will continue to perform this action, expecting more food. If you are interested, you can read on here!