Punishment is the application of an adverse consequent in response to a behavior. The purpose is to decrease the behavior. For example, going to jail is a punishment for committing a crime. Negative reinforcement is the removal of an already adverse condition as a result of a behavior. The purpose is to increase the behavior. For example, if my hitting a loud alarm clock, which I find annoying, silences the alarm, the behavior of hitting the alarm clock is increased, because it was effective in removing the adverse condition.