Do you start salivating when you hear a bell? Then you may be the subject of a test on Pavlovian conditioning and response! Today, we celebrate the birthday of Ivan Pavlov, a Russian physiologist whose work on conditioned reflexes, especially his experiments with dogs, is some of the most famous to date. Pavlov noticed that dogs would begin to salivate before their food was actually delivered to their mouths, and so began conditioning the dogs to associate the sound of a bell with the delivery of food. Soon, Pavlov found that by merely ringing the bell, the dogs would begin to drool in anticipation of their meal, and the rest is history. Pavlov died in 1936 at the age of 86.