Each of these relationships is culturally defined, thus anyone occupying a position is expected to behave in culturally defined ways toward anyone occupying any of the related positions. When a society becomes highly differentiated so that different adult males and adult females are found carrying out a large number of rather different roles, the task becomes much more complex.
Modern theories of class divisions view occupations as the basis of classification within the stratification system. Americans actually view different occupations as superior and inferior to one another. Thompson & Hickey (2005) identify five social classes: upper class, upper-middle class, lower middle class, working class, lower class. This has been demonstrated in countless ways in sociological research. It is thus seen as a means of attainment of social level rather than as a direct measure of social level. It is one of the important links between one's origin and one's destination, not only an influence in determining one's destination, but also influenced by one's origin. A major concern will be to investigate the degree to which one's educational level is a function of one's origin. Thompson & Hickey (2005) identify that adult roles are quite varied, and the socialization experiences required to prepare individuals to carry them out are also quite varied. Such complexities cannot be considered here. There is considerable agreement, however, that a person's occupation is the most valid single measure of the position he occupies in the stratification system of our society. More effectively than any other single measure, occupation reflects all three of the major dimensions of stratification. In fact, this statement probably applies not only to the United States but to all modern industrial societies.
Another classification of class division is proposed by Gilbert & Kahl (2002). This model is based on sources of income which varies within each social class. the authors underline that "there is really no way to establish that a particular model is 'true' and another 'false.'. The main classes are: capitalist class ($250,000 or more), upper middle class ($62,500 per individual), middle class ($50,000 to $90,000 for households), working class ($20,000 to $50,000 for households), working poor ($12,500 per household) and underclass (less than $12,000 a year). There are three important ways in which middle-class occupations differ from working-class occupations that are relevant. First, middle-class (white-collar) occupations typically require the individual to handle ideas and symbols and to be skilled in personal relations, whereas working-class (blue-collar) occupations typically involve physical objects rather than symbols and call for much less interpersonal skill. Second, middle-class jobs require much more self-direction in the ordering of activities and the selection of methods, than working-class jobs, which are more often routinized and subject to more strict supervision. Closely associated with these differences is the tendency for middle-class occupations to call for individual action whereas working-class occupations more often call for coordinated group or team action. Such