This paper describes an experimental test of the role of perceptual organization in the perception and reproduction of a visual stimulus. A perceptually random stimulus was presented to subjects who were to reproduce it. A procedure of serial reproductions was used and the perceptual organization inherent in the subjects' reproductions was quantified by a psychophysical scaling procedure. The prediction of increased organization in successive reproductions was confirmed. When there was little or no perceptual organization in the stimulus (as in the random stimulus), subjects imposed perceptual organization on the sensory input. When there was perceptual organization inherent in the stimulus, subjects perceived it and further emphasized the organization in their reproductions. Of particular interest was the investigation of the distinction between perceptual organization as a characteristic of the sensory input and perceptual organization as a characteristic of the processing operations of the visual system acting on the sensory input.