How does attention spread across objects oriented in depth?

Previous evidence suggests that attention can operate on object-based representations. It is not known whether these representations encode depth information and whether object depth, if encoded, is in viewer-or object-centered coordinates. To examine these questions, we employed a spatial cuing paradigm in which one corner of a 3-D object was exogenously cued with 75% validity. By rotating the object in depth, we can determine whether validity effects are modulated by 2-D or 3-D cue-target distance and whether validity effects depend on the position of the viewer relative to the object. When the image of a 3-D object was present (Experiments 1A and 1B), validity effects were not modulated by changes in 2-D cue-target distance, and shifting attention toward the viewer led to smaller validity effects than did shifting attention away from the viewer. When there was no object in the display (Experiments 2A and 2B), validity effects increased linearly as a function of 2-D cue-target distance. These results demonstrate that attention spreads across representations of perceived objects that encode depth information and that the object's orientation in depth is encoded in viewer-centered coordinates.