Final answer:
Before moving into the intimacy versus isolation stage in Erikson's theory, a person must resolve their identity crisis during adolescence, securing a strong sense of self that enables intimate relationships.
Step-by-step explanation:
According to Erikson's theory, before a person moves into the intimacy versus isolation stage of development, they must resolve their identity crisis that occurs during adolescence. This is known as the task of identity versus role confusion, where adolescents grapple with questions of self and direction. As they emerge from this phase with a strong sense of self, they are prepared to form intimate relationships with others in their early adulthood. Failure to achieve this can lead to feelings of loneliness and emotional isolation as they move into the next stage of their development.