functioning. Optimal development and actions are inherent in humans but they do not happen automatically. Within Self-Determination Theory, Deci & Ryan distinguish between four different types of extrinsic motivation, differing in their levels of perceived autonomy: External regulation: This is the least autonomous of the four and is determined by external punishment or reward. Introjected regulation: This form of external motivation arises when the individuals have somewhat internalized regulations but do not fully accept them as their own. They may comply for self-esteem reasons or social acceptability - essentially internal reasons but externally driven. Identified regulation: This is more autonomously driven - when the individuals consciously perceive the actions as valuable. Integrated regulation: This is the most autonomous form of motivation and the action has been internalized and is aligned with the individual's values, beliefs and is perceived as necessary for their wellbeing. However, this is still classified as extrinsic motivation as it is still driven by external processes and not by inherent enjoyment for the task itself. "16 basic desires" theory Starting from studies involving more than 6,000 people, Reiss proposed that 16 basic desires guide nearly all human behavior. In this model the basic desires that motivate our actions and define our personalities are: Natural theories The natural system assumes that people have higher-order needs, which contrasts with the rational theory that suggests that people dislike work and only respond to rewards and punishment. According to McGregor's Theory Y, human behavior is based on satisfying a hierarchy of needs: physiological, safety, social, ego, and self-fulfillment. Physiological needs are the lowest and the most important level. These fundamental requirements include food, rest, shelter, and exercise. After the physiological needs are satisfied, employees can focus on safety needs, which include “protection against danger, threat and deprivation.” However, if management makes arbitrary or biased employment decisions, then an employee's safety needs are unfulfilled. The next set of needs is social, which refers to the desire for acceptance, affiliation, reciprocal friendships, and love. As such, the natural system of management assumes that close-knit work teams are productive. Accordingly, if an employee's social needs are unmet, then he will act disobediently. There are two types of egoistic needs, the second-highest order of needs. The first type refers to one's self-esteem, which encompasses self-confidence, independence, achievement, competence, and knowledge. The second type of needs deals with reputation, status, recognition, and respect from colleagues. Egoistic