As the Enotes study guide on Romanticism points out, the literary movement (which in America is more commonly referred to as American Transcendentalism) stressed the importance of personal experience over traditionally-accepted values. Romanticism

emphasized the dream, or inner, world of the individual. The use of visionary, fantastic, or drug-induced imagery was prevalent.

This interest on the inner world led people to discover that

there were parts of each individual’s personality beyond the access of ordinary consciousness. This idea was further developed during the twentieth century as part of modern psychological theory, but at the time of the romantics it was a novelty. The romantics were fascinated with self-exploration and with the particulars of the individual’s experience in the world.

In his novels and short-stories, whose literary form he crucially contributed to establish, Nathaniel Hawthorne focused on the exploration of human psychologies with a particular emphasis on man's most secret, repressed and disturbing feelings. Two fellow writers who were to be influenced by Hawthorne's psychological investigations, Henry James and Herman Melville, remarked on the ways in which he was attracted by the study of evil and of disturbed human personalities. Melville famously described Hawthorne as being shrouded in blackness. Hawthorne reacted against the accepted function of literature of presenting experiences that could elevante morally and spiritually. Through his use of metaphors and symbols, he dwelled on a presentation of the darkest aspects of the human psyche, those that society asks us to keep hidden. There are countless examples of this in Hawthorne's oeuvres. In "Young Goodman Brown", the observer of the devil-worshipping orgy is shocked to see many respected citizens there. In "The Minister's Black Veil", the black veil symbolizes the burden of guilt felt by the protagonist. The scarlet letter on Hester's breast is a constant reminder of her sin as well as of the sins of the larger community, Dimmesdale included.