Law (or Principle) Of Positive Reinforcement
The Law (or Principle) of Positive Reinforcement is that "reinforcement" (or reward) must be produced by a positive response to a stimulus. An example of this is when training a dog to sit, you give the command "sit" and when the dog sits you provide it with a food treat. This way the dog learns to associate the reward with responding to the command. This can be considered a concept of the psychological school of behaviorism because it is considered a stimulus response.