Final answer:
True. The formation of identity during adolescence to Erikson's developmental theory and signifies a transition to adulthood, with successful identity formation being crucial for further stages of psychosocial development.
Step-by-step explanation:
The statement in question is true: in Erik Erikson's developmental scheme, the formation of identity indeed marks the transition to adulthood. This occurs during adolescence, which Erikson defined as being from ages 12 to 18. The primary conflict during this developmental stage is identity versus role confusion. Adolescents work through questions about who they are and what they want to achieve in life. Successfully navigating this stage leads to a strong identity, whereas difficulty in this stage can result in role confusion and a weak sense of self, carrying implications into future stages of development, such as intimacy versus isolation in early adulthood.