This theory suggests that genetics are responsible for personality. Behaviorists have shown little interest in the internal structures of personality, but instead focus their interest on personality development. Behaviorists focus their time on how children's response tendencies are shaped through classical conditioning, operant conditioning, and observational learning. Pavlov's concept of classical conditioning is the type of learning in which a natural stimulus acquires the ability to evoke a response originally evoked by another stimulus (Wayne Weiten, 2012, p. 42). The study of operant conditioning was conducted by a man named B.F. Skinner, which is a form of learning in which voluntary responses are controlled by their consequences, which governs a larger share of human behavior than classical conditioning (Wayne Weiten, 2012 , p..