Efficiently representing visual information requires that the observer select only a fraction of the multitude of information that is available to the visual system at any one instant in time. Attentional selection is the mechanism by which a subset of incoming information is extracted from the complex sensory environment. The selection can be achieved in a top-down, goal-directed fashion (e.g., when one sets out to find one's keys on the kitchen counter), or in a bottom-up fashion in response to highly salient or novel stimuli in the input (e.g., a red strawberry among greener strawberries on a bush captures the viewer's attention). Early models of attentional selection suggested that attention is directed to particular regions or locations in space (the region of the keys or ...