A broad social grouping based upon level of prestige determined by such characteristics as occupation, income, family genealogy, moral standing, residential area, and social relationships.Class is distinguished from caste by the fact that the boundaries of the class group are less rigid. A caste system, as in India, is based on hereditary distinctions, and the lines cannot be crossed without incurring severe social punishment. A class system, on the other hand, permits a degree of social mobility or crossing of class lines. America is predominantly a class system, though the color line has some features of a caste system, such as discouragement of “mixed” neighborhoods and illegality of intermarriage in certain states.In the present period rigid class distinctions are slowly breaking down, and social mobility is on the increase. A study by Lipset and Bendix (1959) has indicated that it is particularly high in the occupational sphere, at least among nonfarm workers, both in this country and abroad. Their findings show that from 29 to 45 per cent of the population have been shifting upward from manual to nonmanual work between generations, while 13 to 32 per cent have shifted downward from nonmanual to manual occupations.The idea that American society has a class structure is often denied; yet it appears to have been demonstrated by a number of sociological investigations —notably Warner and Lunt’s study of an old New England city (“Yankee City”) in 1941, and Warner, Meeker and Eells’ survey of a Midwestern town (“Jonesville”) in 1949. These studies were based on interviews in which large numbers of citizens were asked to rate their fellow townsmen on social status. The subjects were free to use their own criteria, which were in general those enumerated in the definition of social class given at the head of this article, with the greatest emphasis on occupation and economic level. An analysis of the results showed that the subjects viewed their fellow townsmen in terms of three major classes, each with a lower and upper level; and the comparison between percentages in New England and Midwestern cities showed, interestingly, that they were remarkably similar: upper-upper, 2 per cent and 3 per cent; lower-upper, 2 per cent and 3 per cent; upper-middle, 10 per cent and 11 per cent; lower-middle, 28 per cent and 31 per cent; upper-lower, 33 per cent and 41 per cent; lower- lower, 25 per cent and 14 per cent.A number of significant studies have been made of the psychological and social effects of class structure. One important finding is that even where the classes are not rigid and mobility is possible, as in America, there is still a great difference in the prestige of the different classes and in the power, respect, and honors which they command. It has frequently been shown, for example, that even at the grade school level children consider people from the higher social classes more attractive than those from the lower classes (Bonney, 1944). Other investigators have found that members of the higher classes are somewhat freer than members of lower classes to violate group mores and to deviate from group opinions, that they are accorded greater opportunities to speak and voice their opinions in group discussions, and that people are more likely to believe them and follow their lead than to be influenced by individuals from lower social levels.Another major finding is that social level to a great extent determines the entire environment of the individual, including opportunities for completing high school and going to college, leisure- time activities, general values of life, and type of job. Recent studies have indicated that children brought up in a deprived environment are often grossly handicapped in sensory discrimination, motor skills, vocabulary and problemsolving ability due to lack of opportunity for normal communication, diversified play activities and varied stimulation in their homes. As Davis and Havighurst pointed out in 1946, ‘The social-class system maintains cultural, economic and social barriers which prevent intimate social intermixture between the slums, the Gold Coast, and the middle class ... By setting up barriers to social participation, the American social-class system actually prevents the vast majority of the working classes, or the slums, from learning any culture but that of their own group. Thus the pivotal meaning of social class to students of human development is that it defines and systematizes the different learning environments for children of different classes.”Psychological investigations have shown that social classes differ not only in status and opportunity but in the attitudes, behavior and personalities of their members. Some of these findings will be briefly summarized. It is a well- recognized fact that the higher the class of the individual, the more likely he is to hold conservative political opinions (although there are many exceptions). In another sphere, Kinsey et al. (1948)found significant differences in sexual behavior on different levels of society. The semiskilled-labor group engaged in considerably more premarital intercourse and considerably less masturbation than the professional group, with the lower white collar group intermediate between the two. Interestingly, people who ultimately moved from the skilled-labor to the professional class manifested sexual patterns similar to those of the class to which they moved, and the same principle held if they moved downward to the unskilled-labor class.Studies have also shown that young people from the upper and middle social strata not only show a higher level of achievement-motivation than children from the lower levels (Rosen, 1956), but are also more likely to have personal values and characteristics that make for occupational success. In addition, a number of investigations have been made of class differences in child- rearing practices and their effect upon personality development.