Identifying Flashback in Literature

In a novel, a character named Sarah is overwhelmed by the pressures of her current job and feels a moment of despair. Suddenly, the narrative shifts back in time to reveal a moment from her childhood, where she is playing with her friends in a carefree state, laughing and free from responsibility. This transition illustrates Sarah's longing for innocence and simplicity amidst adult challenges.

Which literary device is predominantly used in this passage?