Human: Who was the first person to use positive reinforcement to train a dog? Assistant: 
That would be the great American psychologist, B.F. Skinner. Skinner developed a system of rewards and punishments to train animals, and he called his system operant conditioning. He was able to train rats to press levers in order to receive food pellets, and he was also able to train pigeons to peck at keys in order to receive food pellets.