Behavior analysis is a specific scientific approach to studying behavior that evolved from John Watson's behaviorism and the operant research model popularized by B. F. Skinner during the middle of the 20th century. This approach stresses direct experimentation and measurement of observable behavior. A basic assumption of behavior analysis is that behavior is malleable and controlled primarily by consequences. B. F. Skinner described the basic unit of behavior as an operant, a behavior emitted to operate on the environment. Additionally, he proposed that the response rate of the operant serve as the basic datum of the scientific study of behavior. An operant is characterized by a response that occurs within a specific environment and produces a specific consequence. According to the principles of operant conditioning, ...