English, German, and American youth from pubescence to late adolescence were interviewed in order to discern the maturation of political perspectives. By comparing youngsters in three countries with different political traditions, the differential impact of social ideas was examined. At each age level subjects were matched for sex and I.Q. and, the national samples were matched for age, sex, and I.Q. Cognitive maturation was found to be involved in the developmental changes observed. For adolescents from all three countries the following was found: (1) a shift from concrete to abstract modes of discourse, and from concrete to formal operations (Piaget) in analyzing political problems, (2) a decline in authoritarianism and a growth in democratic and humanistic views of social and political issues, (3) a shift from a punitive to a rehabilitative emphasis in dealing with crime, (4) an increased understanding of the needs of the total community as against the single individual, and (5) in general, a change from absolutistic to relativistic and pragmatic ways of formulating political issues. The patterns of political thought unique to each of the national samples are presented. (PS)