Behaviorism is a psychological theory that focuses on observable behaviors and believes that behaviors can be shaped through conditioning using reinforcement and punishment. Key behaviorist theorists include Ivan Pavlov, John Watson, Edward Thorndike, and B.F. Skinner. In a classroom setting, a teacher can use behaviorism by positively reinforcing good behaviors like allowing extra computer time or giving treats, and negatively reinforcing bad behaviors through punishment like time outs or removing privileges. Students learn what behaviors are acceptable through these reinforcements.