When does differentiation appear fully developed?
Further distinctions in self-concept, called "differentiation," occur as the adolescent recognizes the contextual influences on their own behavior and the perceptions of others, and begin to qualify their traits when asked to describe themselves. Differentiation appears fully developed by mid-adolescence. Peaking in the 7th-9th grades, the personality traits adolescents use to describe themselves refer to specific contexts, and therefore may contradict one another. The recognition of inconsistent content in the self-concept is a common source of distress in these years (see Cognitive dissonance), but this distress may benefit adolescents by encouraging structural development.
According to a study done by Helmut Fend (who had always been a fierce proponent of comprehensive schools) revealed that comprehensive schools do not help working class students. He compared alumni of the tripartite system to alumni of comprehensive schools. While working class alumni of comprehensive schools were awarded better school diplomas at age 35, they held similar occupational positions as working class alumni of the tripartite system and were as unlikely to graduate from college.