Object-Based Attention Guided by An Invisible Object

Many studies have demonstrated that attention can be object based. One line of evidence supporting object-based attention showed that observers respond to a target faster when the target and cue are in the same object than when they are in different objects, which is called the same-object advantage. By adopting the double-rectangle cuing paradigm (Egly, Driver, & Rafal, 1994), we tested whether this advantage can occur with invisible rectangles. The original paradigm was slightly modified. Rectangles had a low luminance level against a dark background and were presented for only 10 ms, along with a cue or a target. These two characteristics rendered the rectangles invisible to subjects, as confirmed by a forced-choice test. We found a conventional object-based attention effect even when the rectangles were invisible. We also found that the object-based attention was dependent on the orientation of the rectangles presented along with the target, consistent with the finding by Ho and Yeh (2009). These results suggest that object based attention can be guided by an invisible object in an automatic way, with a minimal influence from the high level top-down control.