Perception of object movement during self-movement

Motion of the image of an object across the retina may be due to movement of the object, movement of the observer or a combination of the two. The human brain has a well-documented sensitivity to "flow" - the characteristic pattern of retinal motion resulting from movement of the observer's eye through the environment (self-movement). If the pattern of flow due to self-movement could be parsed out then any remaining retinal motion could be attributed to movement of an object within the environment (object-movement). We review the results of three studies conducted recently on detection of movement, induced movement and visual search. The results of all three studies are compatible with the flow-parsing hypothesis described above. The commonly held assumption that the primary role of flow processing is in the guidance of locomotion has been disputed. Here we suggest an alternative role in which flow processing does not control but compensates for locomotion