Pavlov’s bell is a type of conditioning first described by Ivan Pavlov. It is a process whereby a conditioned stimulus (in this case, a bell) is paired with an unconditioned stimulus (in this case, food) to produce the desired response (in this case, drooling). The bell is rung, and the food is presented, causing the dog to salivate. After some time, the bell is rung without the food being presented, and the dog still drools. The conditioned stimulus has now become associated with the unconditioned stimulus, and this response is known as conditioning. Conditioning can be used to produce a variety of desired responses in animals and humans alike. It is a powerful tool that can be used to shape behavior.