Need

A need is the psychological feature that arouses an organism to action toward a goal and the reason for the action, giving purpose and direction to behavior.

The most widely known academic model of needs was proposed by Abraham Maslow. In it, he proposed that people have a hierarchy of needs, which range from security to self actualization. However, while this model is intuitively appealing, it has been difficult to operationalize it experimentally. It was further developed by Clayton Alderfer.