Seite - 128 - in Psychoanalytic Perspectives on Puberty and Adolescence - The Inner Worlds of Teenagers and their Parents

128 Development of thinking or philosophy. It thus can be said that adolescents between 15 and 20 years attain this stage of formal operations in various areas, according to their interests or (future) professional specialization. Note 1 “Stage” is also translated as “period”. The number of stages varies, since some texts describe the sub -stages as their own independent stages (thus comprising four separate stages).