Operant conditioning is a method of learning through reinforcement and punishment of behaviors. Reinforcements, like rewards, increase the likelihood a behavior will be repeated, while punishments decrease likelihood a behavior will be repeated. Skinner used a technique called shaping to teach behaviors to animals like pigeons by breaking behaviors into small, reinforced steps to build up to a complex behavior. Shaping involves giving reinforcement for closer and closer approximations of the desired behavior until the behavior is learned. The technique was effective for pigeons but not all animals, like raccoons. Shaping can also be used to teach humans complex behaviors by reinforcing successive steps.