Behaviorism is a learning theory that states all behaviors are learned through interaction with the environment, specifically through conditioning. It focuses only on observable behaviors that can be systematically studied. The behaviorist movement began in 1913 emphasizing environmental influences on behavior and the role of learning through conditioning rather than innate factors. Behaviorism uses principles of classical and operant conditioning to modify behavior through reinforcement or punishment. In classroom settings, behaviorism is applied through strategies like positive reinforcement, drills, guided practice, and regular reviews to shape student behavior and learning.