Kurt Lewin's theory of adolescence proposes that adolescents are in a transition period between childhood and adulthood where they do not fully belong to either group. According to the theory, adolescents experience rebellious attitudes, vulnerability, and hormonal changes during this transition. Lewin also believed that an individual's "life space" is shaped by past, present, and future events and their needs in interaction with their psychological environment. He promoted sensitivity training for educators to understand adolescents and reduce conflicts during this developmental period of uncertainty.