The second stage of feature integration theory is the focused attention stage, where a subject combines individual features of an object to perceive the whole object. Combining individual features of an object requires attention, and selecting that object occurs within a "master map" of locations. The master map of locations contains all the locations in which features have been detected, with each location in the master map having access to the multiple feature maps. When attention is focused at a particular location on the map, the features currently in that position are attended to and are stored in "object files". If the object is familiar, associations are made between the object and prior knowledge, which results in identification of that object. In support of this stage, researchers often refer to patients suffering from Balint's syndrome. Due to damage in the parietal lobe, these people are unable to focus attention on individual objects. Given a stimulus that requires combining features, people suffering from Balint's syndrome are unable to focus attention long enough to combine the features, providing support for this stage of the theory.