While studying conditioned reflexes in the early 20th century, scientist Ivan Pavlov found that if he rang a bell every time he fed dogs, they learned to salivate when they heard the bell, whether they were being fed or not. Today I noticed that at certain times of day our dog gets excited (running around in circles) if you pick up an iPod. Why? Because that usually means it's time for a walk! Has anybody else noticed this? Don't forget: If YOU smile when you pick up your iPod, that's a conditioned reflex too!