Perceptual learning in seeing form from motion.

Some perceptual tasks, such as global stereopsis, have been shown to improve with practice. Paradigms that involve such 'perceptual learning' have been exploited to learn more about the nature and sites of these perceptual tasks in the brain and about plasticity in the adult central nervous system. We found that seeing structure from global motion in some kinematograms composed of tilted line elements required a period of learning. However, such learning was specific neither to the orientation of the line elements nor to the direction of global motion, even though detection of these line elements and the direction of motion was necessary for seeing the global structure in these kinematograms. Our results suggest that the neural site of deriving form from motion is beyond the level of individual motion and pattern detectors. In both its nature and locus along the hierarchy of the visual system, this learning is quite different from other types of perceptual learning reported so far.