A thing, event or action given to
someone to ensure that they behave the
way you want them to. The term
may be applied to the person who does it.
Not to be
confused with 'enforcer' which is a person paid to punish those who fail to do something such as abide by a rule or agreement
Usually used to describe negative or unpleasant, when the person knows they are being controlled, but equally applies to pleasant or positive event, when the person usually doesn't know they are being controlled but thinks they are doing it because they want to. Positive reinforcers are more subtle and more effective.