Neobehaviourism is a system of psychology that followed behaviourism with no clear separation between the two, and is predominantly associated with B. F. Skinner. The neobehaviourist movement lasted from approximately 1930 to 1960 and supported the idea that all learning and behavior can be described in terms of conditioning. Operant conditioning (or instrumental conditioning) is a term coined by B. F. Skinner in 1937 and is a type of learning in which an individual’s behavior is modified by its consequences; the behaviour may change in form, frequency, or strength. Reinforcement and punishment are the core tools of operant conditioning and they are either positive or negative: positive reinforcement is the adding of an appetitive stimulus (a pleasant outcome) to increase a certain behavior or response. Positive punishment is the adding of an aversive stimulus (an unpleasant outcome) to decrease a certain behavior or response. Negative reinforcement consists of the taking away of an aversive stimulus to increase a certain behavior or response, and negative punishment is the taking away of an appetitive stimulus in order to decrease a certain behavior.