The second stage of processing depends on attention. In this stage, the features are combined, resulting in the perception of a whole object rather than individual features. Treisman linked this process of binding to neural activity, noting that an object causes activity in both the "what" and "where" areas of the cortex (see Two-streams hypothesis). Activity in the "what" processing stream would include information about color and form, while activity in the "where" stream would include information about location and motion. According to Treisman, attention is the "glue" that combines the information from both streams and causes us to perceive all the features of an object as combined at one specific location. Perceiving one object in isolation appears relatively straightforward, but when we confront multiple objects, numerous features may exist at different locations. The perceptual system's task is to associate each of these features with the object to which it belongs. Feature integration theory says that in order for this to occur, we need to focus our attention on each object in turn. Once we attend to a particular location, the features at that location are bound together and are associated with the object at that location.