Abstract
Attention to an exogenously cued location is initially facilitated and then inhibited (Posner and Cohen, 1984). However, it remains unclear how the time course of spatial attention interacts with feature-based attention. Here, we investigated the effect of cue-to-target feature similarity on spatial and temporal attentional allocation. A variant of the Posner cueing paradigm was used where cue and probe circles were presented at varying inter-stimulus intervals (ISIs) (50, 150, 350, 700ms) in random locations (left, right). The colors of the cue and the probe were chosen from four evenly distributed colors (orange, yellow-orange, orange-yellow, yellow). Subjects responded to the location of a target-colored (orange or yellow, counterbalanced) probe, and withheld responses for other-colored probes (catch trials). The portion of catch trials was 10% in Experiment1 (N=18), and 50% in Experiment2 (N=18). In Experiment1, there was an interaction between cue-color and ISI. For target-similar cues (e.g., orange and yellow-orange cues for orange targets), the amount of attentional facilitation in the cued location decreased as ISI increased, but never switched to the uncued location, even at the longest ISI. This was in contrast to inhibition-of-return (IOR) effects observed in a control experiment. For target-dissimilar cues (e.g., yellow and orange-yellow cues for orange targets), there was no facilitation for the cued location early on, and the magnitude of facilitation in the uncued location increased with ISI as a function of the physical and categorical similarity between the cue and the target. In Experiment2, similar effects were found for target-similar cues, but now subjects became more sensitive to target-dissimilar cues. This resulted in facilitation in the uncued location even at the shortest ISI, indicating greater attentional suppression of target-dissimilar cues. These results suggest that the feature and categorical similarity between the cue and the target dynamically interact with the time course of spatial attention.
Meeting abstract presented at VSS 2014