1. Learning: Concept that when people become aware of a deficiency in their competence they are motivated to learn, and the anxiety caused by the discrepancy between what they know and what they need to know drives them to make the required effort (change of behavior).
2. Human resource management: Concept that job satisfaction (or lack of it) arises from the discrepancy between what income an employee thinks he or she deserves to get and is actually getting, as well as what income others deserve and are actually getting.