Davis and Moore’s article, Some Principles of Stratification, is an attempt to explain social stratification in terms of the function that stratification plays in all social systems. The starting point for the article is one that claims that all societies exhibit some degree of social stratification.
The basic form of society might seem static, but there is a process at work as people are born, live, and eventually die. This process must cope with the introduction and loss of individuals. All societies need to motivate individuals to fill the various roles and positions that allow society to function as a system. This basic need for motivation is what gives rise to social stratification and inequality. Society must convince individuals to fill various positions and to perform the tasks required of the position. In essence there are two types of motivation that society must provide, the motivation to fill the role, and the motivation to perform the task.
Positions within a society vary in terms of the pleasantness of the position, skills required, and functional importance to the society. Society needs an efficient way to fill these roles with those individuals who are capable of performing the tasks associated with the role diligently. Rewards offer the motivation for individuals to seek out positions within society. Examples of the rewards that societies have to motivate individuals include: material gain and comfort, entertainment and distraction, and social prestige. The rewards can be built into the position in the form of accompaniments and rights that are functionally related to the position. Often there are also rights that are not functionally related to the duties of the position, but nonetheless provide incentive for individuals to fill the roles. Given that rewards and rights must be unequally distributed throughout society, stratification is a necessity for society to function. The type and amount of stratification a society displays will vary, but the aforementioned reasoning is why there cannot be a functioning society without some degree of stratification and inequality.
There are two factors that determine the ranking and rewards given to positions within society. Generally, roles that are ranked the highest are those that are vital for the functioning of society, or that require great natural talent or lengthy training periods, or both. If a position is functionally important but easily filled, the rewards need not be great for the position to be competently filled. However if the position is functionally very important and difficult to fill, the rewards and ranking must be high in order to induce individuals to fill the position. Personnel can be scare for two reasons, the rarity of natural talent, or lengthy, expensive and difficult training periods. When the position requires a rare natural talent, the reward must be great in order to limit competition from other positions and ensure that the few talented individuals are motivated to accept the position and perform the tasks required. When a position requires expensive, lengthy, and difficult training, society must provide adequate reward to entice individuals to undertake the challenge of completing the training program.