Hierarchy of Needs is developed by Abraham Maslow. It is the notion that people are motivated to satisfy basic physiological needs such as food, shelter, etc. before moving on to satisfying higher psychological needs such as security, companionship, etc.. These alternative needs are layered in a hierarchial pattern with physiological needs on the bottom, safety needs on the second layer, belonging needs on the third layer, esteem needs on the fourth layer, and self-actualization needs at the top. This hierarchy of needs has been used to help explain the progress of human societies from agrarian to manufacturing to service to information.