Final answer:
The likely result of an adolescent not successfully achieving a sense of self in Erikson's identity versus role confusion stage is confusion about their future and potential difficulty with future stages of psychosocial development, such as forming intimate relationships.
Step-by-step explanation:
Concerning Erikson's psychosocial development theory, the likely result of an adolescent not successfully achieving a sense of self during the identity versus role confusion stage is that they will be confused about their future. This stage is crucial for adolescents, who ask themselves "Who am I?" and "What do I want to do with my life?" Attempting different roles helps them establish a strong identity, which is essential for moving forward confidently. Without this sense of identity, adolescents may struggle with role confusion, leading to uncertainty and inability to remain true to their beliefs when challenged.
Moreover, if adolescents do not develop a firm sense of self, they may have difficulty with movement into the intimacy vs isolation phase in early adulthood. Erikson emphasized the importance of having a strong identity before forming intimate relationships, as adults without a positive self-concept may experience loneliness and emotional isolation.