Final answer:
The psychosocial stage most pertinent to 18-19-year-olds is Identity vs. Role Confusion, focusing on the development of a strong personal identity and the embrace of one's beliefs and values.
Step-by-step explanation:
Psychosocial Growth Ages 18-19 (Late Adolescence)
The stage of psychosocial development that typically concerns individuals aged 18-19, which falls under late adolescence, is Identity vs. Role Confusion. This stage, conceptualized by Erik Erikson, is a continuation of the process that starts earlier in the adolescent years. It revolves around the development of a personal identity, finding an answer to the question, "Who am I?" Adolescents at this phase examine their values, beliefs, and goals to solidify their sense of self. Those who successfully navigate this stage emerge with a strong sense of identity and the ability to stay true to their beliefs amidst challenges.
On the other hand, those who do not actively seek to formulate their identity or who are pushed to conform to others' expectations may face role confusion, resulting in a weak sense of self and uncertainty about their future. Growth during this period implies not only physical changes but significant psychosocial changes, including establishing a more definitive sense of self and, possibly, preparing for the next Eriksonian stage, which is Intimacy vs. Isolation, occurring in early adulthood.