Visual attention is a single, integrated resource.

Recent evidence for separate forms of attention for different visual attributes seems to conflict with Duncan's "integrated competition" theory of visual attention. To resolve this conflict, we established attention-operating characteristics for four pairs of visual discriminations. While one task was common to every pair, the other tasks were different and concerned different visual attributes. In all pairs, the common task exhibited the same performance-resource function, whether the other tasks involved entirely similar, partially similar, or entirely dissimilar visual attributes. These results confirm that visual attention conforms exactly to the predictions of a single, integrated resource.