In psychogeography, a dérive is an unplanned journey through a landscape, usually urban, on which the subtle aesthetic contours of the surrounding architecture and geography subconsciously direct the travellers, with the ultimate goal of encountering an entirely new and authentic experience. Situationist theorist Guy Debord defines the dérive as "a mode of experimental behavior linked to the conditions of urban society: a technique of rapid passage through varied ambiances." He also notes that "the term also designates a specific uninterrupted period of dériving." The term is literally translated into English as drift.
The concept of the dérive has its origins in the Letterist International of the 1940s, an artistic and political collective based in Paris, where it was a critical tool for understanding and developing the theory of psychogeography, defined as the "specific effects of the geographical environment (whether consciously organized or not) on the emotions and behavior of individuals." The dérive, an unplanned tour through an urban landscape directed entirely by the feelings evoked in the individual by their surroundings, served as the primary means for mapping and investigating the psychogeography of these different areas.
The dérive continued to be a critical concept in the theory of the Situationist International, the radical group of avante-garde artists and political theorists that succeeded the Letterist International, emerging in the 1950s. For the situationists, the dérive is the primary technique for exploring an urban landscape's psychogeography and engaging in new experiences. According to situationist theorist Guy Debord, in performing a dérive, the individual in question must first set aside all work and leisure activities and all their other usual motives for movement and action, and let themselves be drawn by the attractions of the terrain and the encounters they find there.
The need for the dérive is necessitated, according to situationist theory, by the increasingly predictable and monotonous experience of everyday life trudged through every day by workers in advanced capitalism. The dérive grants a rare instance of pure chance, an opportunity for an utterly new and authentic experience of the different atmospheres and feelings generated by the urban landscape. Debord observes in his Introduction to a Critique of Urban Geography:
The sudden change of ambiance in a street within the space of a few meters; the evident division of a city into zones of distinct psychic atmospheres; the path of least resistance that is automatically followed in aimless strolls (and which has no relation to the physical contour of the terrain); the appealing or repelling character of certain places — these phenomena all seem to be neglected. In any case they are never envisaged as depending on causes that can be uncovered by careful analysis and turned to account.—Guy Debord, Introduction to a Critique of Urban Geography
Several groups have adopted the concept of the dérive and applied it in their own form, including many modern organizations, most notably the London Psychogeographical Association and the Providence Initiative for Psychogeographic Studies. Since 2003 in the United States, separate events known as Provflux and Psy-Geo-conflux have been dedicated to action-based participatory experiments similar to the dérive, within the context of psychogeography.
See also 
- Guy Debord (1958) Definitions. Internationale Situationniste #1 (Paris, June 1958). Translated by Ken Knabb.
- Guy Debord (1956) Theory of the Dérive. Les Lèvres Nues #9 (Paris, November 1956). Reprinted in Internationale Situationniste #2 (Paris, December 1958). Translated by Ken Knabb.
- Guy Debord (1955) Introduction to a Critique of Urban Geography. Les Lèvres Nues #6 (Paris, September 1955). Translated by Ken Knabb.