The Kuleshov Effect is a montage effect demonstrated by Russian filmmaker Lev Kuleshov in about 1918.
Kuleshov edited together a short film in which a shot of the expressionless face of Tsarist matinee idol Ivan Mozzhukhin was alternated with various other shots (a plate of soup, a girl, an old woman's coffin). The film was shown to an audience who believed that the expression on Mozzhukhin's face was different each time he appeared, depending on whether he was "looking at" the plate of soup, the girl, or the coffin, showing an expression of hunger, desire or grief respectively. Actually the footage of Mozzhukhin was the same shot repeated over and over again. Vsevolod Pudovkin (who later claimed to have been the co-creator of the experiment) described in 1929 how the audience "raved about the acting.... the heavy pensiveness of his mood over the forgotten soup, were touched and moved by the deep sorrow with which he looked on the dead woman, and admired the light, happy smile with which he surveyed the girl at play. But we knew that in all three cases the face was exactly the same." [Pudovkin, "Naturshchik vmesto aktera", in Sobranie sochinenii, volume I, Moscow: 1974, p.184].