Final answer:
In adulthood, according to Erikson's developmental theory, the task to be accomplished is integrity versus despair, where individuals reflect on their lives and feel either a sense of satisfaction or regret.
Step-by-step explanation:
Erikson's developmental theory posits that in adulthood, the task that should be accomplished is integrity versus despair. This is part of his psychosocial theory which maps out eight stages of development from infancy through late adulthood. Each stage is characterized by a specific conflict or task. In late adulthood, individuals reflect on their lives and either attain a sense of integrity, feeling content with their accomplishments and accepting their life's path, or succumb to despair, feeling regret and unfulfilled. Successfully navigating this stage is crucial for achieving a healthy personality and a sense of competence.