Behaviorism is the theory that all behaviors are acquired through conditioning from interactions with the environment, without consideration of internal mental states. Key figures who developed behaviorism include John B. Watson, who claimed psychology would concern only observable behaviors, and B.F. Skinner, who developed operant conditioning to explain how behaviors are influenced by their consequences. Behaviorism can be applied in classrooms through positive reinforcement of good behaviors and punishment of bad behaviors to change student learning outcomes.