Simply, the learner will repeat the desired behaviour if a positive reinforcement (a pleasant consequence) follows the behaviour. Negative reinforcement refers to a situation when a negative condition is stopped or avoided as a consequence of the bahaviour (for example, applying sunscreen to stop getting burnt). Punishment, on the other hand, teaches the individual not to repeat the behavior which was negatively reinforced (for example, grounding your daughter because she stayed out all night).
However, Skinners assumed that everything that happens (including behavior) is shaped by past events, therefore rejecting freewill.
Skinner later acknowledged that in order that mankind would survive, people needed to change their behavior by overcoming pride, letting go of aggression and giving yourself a purpose. This may seem pessimistic, however, skinner knew that people will not react to preserve the world until its too late.
This basic idea assumes that any irrational behavior can be punished, therefore, stopping the behavior. Whereas good behavior is rewarded. Over a period of time any negative or irrational behavior is likely to disappear as the individual will realize that such behaviours lead to punishement through this form of conditioning where association can be made through behavior and consequence. For example, excesesive eating leads to weight