Abstract
In the influential two-rectangle paradigm, attention is preferentially allocated to cued objects over noncued objects (Egly et al, 1994). Improved performance within the cued object manifests itself as a manual reaction time and accuracy advantage. However, no study to date has systematically investigated how saccadic reaction time is affected by object-based attention. Our goal is to determine whether saccade latencies are affected by space-based attention alone or whether object-based attention also plays a role. We employed a modified version of the classic two-rectangle paradigm coupled with a saccade reaction time task. Two horizontal or vertical rectangles (orientation blocked), were presented with an exogenous spatial cue flashed at one end of one rectangle. A target gray disk then appeared at one end of one object on 80% of trials (20% target absent). Of target present trials, 75% were valid trials in which the target appeared at the cued location, and on invalid trials (25%) the target appeared equally likely at the uncued end of the cued object (invalid-same object), or at an equidistant location on the uncued object (invalid-different object). Participants were instructed to make a single saccade to the target. Results showed that the saccadic latency was fastest on valid trials. Moreover, saccadic latency was significantly faster during invalid-same object trials versus invalid-different object trials. This effect was found for both the vertical and horizontal rectangle configurations. These results indicate that the oculomotor system is not only involved in location-based saccade preparation, but it is also guided by object-based attention. The eye-movement planning system may, therefore, be subject to the same boundary conditions that determine the representational basis of attentional selection in the visual scene.
Meeting abstract presented at VSS 2015