Object-based attention in real-world scenes

We are continually confronted with more visual information than we can process in a given moment. In order to interact effectively with our environment, attentional mechanisms are used to select subsets of environmental properties for enhanced processing. Previous research demonstrated that spatial regions can be selected based on either their low-level feature or high-level semantic properties. However, the efficiency with which we interact with the world suggests that there must be an additional, midlevel, factor constraining effective attentional space. The present study investigates whether object-based attentional selection is one such midlevel factor that constrains visual attention in complex, real-world scenes. Participants viewed scene images while their eye movements were recorded. During viewing, a cue appeared on an object which participants were instructed to fixate. A target then appeared either on the same object as the cue, on a different object, or floating. Participants initiated saccades faster and had shorter response times to targets presented on the same object as the fixated cue. The results strongly suggest that when attending to a location on an object, the entire object benefits perceptually. This object-based effect on the distribution of spatial attention forms a critical link between low- and high-level factors that direct attention efficiently in complex real-world scenes.