Abstract
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 re-evaluate the role of uncertainty in object-based attentional guidance. In a series of experiments, we examine the extent to which temporal uncertainty influences object-based attention. 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. In the Mixed Temporal Uncertainty experiment, uncertainty was manipulated by introducing a distribution of delays for the onset of the display with a mean of 2000ms and a standard deviation of 500ms in the uncertain condition and a constant delay of 2000ms in the certain condition. In the Varied Temporal Uncertainty experiment, uncertainty was manipulated by either introducing a distribution, with a mean of 1500ms and a standard deviation of 200ms, for the uncertain condition or a less varied distribution, with a mean of 1500ms and a standard deviation of 50ms, for the certain condition. Effect of compatibility was observed for all temporal uncertainty experiments, with incompatible flankers interfering to a greater extent than compatible flankers. Object based flanker interference was also found under conditions of temporal uncertainty, such that greater flanker interference was observed for targets and flankers that appeared on the same object as compared to when flankers appeared on a different object. We conclude that uncertainty is a major determining factor in object-based guidance of attention, with object-based representations influencing attention selection when temporal uncertainty is high. Additionally, these results provide strong evidence that uncertainty in general, not just spatial uncertainty, predicts object-based attention.
Meeting abstract presented at VSS 2014