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It is often claimed that visualizing and perceiving interfere with each other because they compete for special purpose visual processing resources. The arguments for this view (e.g. Brooks, 1967, 1968) are criticised. Five experiments are then reported which attempt to determine whether specific processing activities interfere with the visualization of novel abstract patterns. Visualization was greatly interfered with by adding five digits but not by reading them. Presentation modality of the digits did not affect the interference they caused. When the intervening activity involved processing patterns similar to those being visualized, the amount of interference depended upon whether the subject had to form and use representations that outlived the icon. Perception caused interference when it involved formation of a maintainable representation, but not when it required only sensory storage. It is concluded that visualization requires general purpose resources, and that interference between visualization and perception could be due to competition for these resources.
Phillips et al. (Tue,) studied this question.