When? What? The Effect of Temporal and Identity Uncertainty on Object-Based Attentional Selection
23.309, Saturday, May 11, 8:30 am - 12:30 pm, Royal Ballroom 6-8
Breana Carter1, Sarah Shomstein1; 1George Washington University
Several lines of evidence suggest that object representations contribute to attentional guidance under conditions of high spatial uncertainty (Drummond & Shomstein, 2010). Others suggest that object representations guide selection even when spatial certainty is high (Chen & Cave, 2006). Here, we directly evaluate the role of uncertainty in object-based attention guidance. In a series of experiments, we examine the extent to which different types of uncertainty (temporal and identity), influence object-based attention in the presence of high spatial certainty. Using a display consisting of three rectangles, arranged in a cross-shape, flanker interference was measured as a function of whether flankers appeared on the same or different object. The target always appeared in the center of the screen producing high spatial certainty. Temporal uncertainty was manipulated by varying delay between the onset of the display and the target (1000ms and 2000ms) in the uncertain condition and a constant delay (1000ms or 2000ms) in the certain condition. Identity uncertainty was manipulated by either reducing or increasing the target item set. Effect of compatibility was observed for both types of uncertainty, with incompatible flankers interfering to a greater extent. Interestingly, however, object based flanker interference was only observed under conditions of temporal uncertainty. These results strongly suggest that uncertainty is a major determining factor in object-based guidance of attention, with object representations influencing attention when uncertainty is high. Additionally, results indicate that not all types of uncertainty contribute equally to object-based guidance of attention, thus providing further constraints on mechanisms of attentional selection.