A "joke" is an incongruous or tendentious verbal message, which, by discharging its psychic energy, gives the listener pleasure. Characteristically a joke is not fabricated (manufactured); rather it emerges as a spontaneous, involuntary idea (Einfall) and briefly returns the person to an infantile mode of cognition. Wit is, according to Freud, "the most social of activities, designed to provide pleasure through the simple and disinterested activity of the psychic apparatus" (1905c).

Freud devoted an important work, Der Witz und seine Beziehung zum Unbewussten (Jokes and Their Relation to the Unconscious, SE, 8), to jokes and their relation to the unconscious (1905c). Published five years after The Interpretation of Dreams (1900a), this essay confirmed the usefulness of the principal processes it described, such as the transformation of thoughts into images (metaphor), condensation, and...