Beginning with abstract free association, in the 1930s many surrealists moved on to a more literal illustrative rendering of dream imagery. In a work like Renee Magritte's The Voice of Space, for example, the free-associative element resides in the selection of the imagery rather than the method through which the subject is expressed.

Surrealism evolved out of the Dada trenches in the early 1920s, directed by the poet Andre Breton. Influenced by their contemporaries, the French Freudian psychoanalysts, the surrealists looked ot the unconcious mind as the source of artistic inspiration. As written in The Surrealist Manifesto, Breton defined surrealism as "pure psychic automatism by which one intends to express verbally, in writing or by other method, absence of any control exercised by reason, and beyond any aesthetic or moral preoccupation."