Top-down control in time and space: Evidence from saccadic latencies and trajectories

Abstract

Visual distractors disrupt the production of saccadic eye movements temporally, by increasing saccade latency, and spatially, by biasing the trajectory of the movement. The present research investigated the extent to which top-down control can be exerted over these two forms of oculomotor capture. In two experiments, people were instructed to make target directed saccades in the presence of distractors, and temporal and spatial capture were assessed simultaneously by measuring saccade latency and saccade trajectory curvature, respectively. In Experiment 1, an attentional control set manipulation was employed, resulting in the elimination of temporal capture, but only an attenuation of spatial capture. In Experiment 2, foreknowledge of the target location caused an attenuation of temporal capture but an enhancement of spatial capture. These results suggest that, whereas temporal capture is contingent on top-down control, the spatial component of capture is stimulus-driven.

Keywords:

• Attention
• Capture
• Control
• Saccade
• Curvature

Acknowledgements

This work was supported by an NSERC Discovery Grant to Jay Pratt and an NSERC Canadian Graduate Scholarship to NA.

Notes

¹It is unclear, however, whether this contingency reflects an attentional filter (Chen & Mordkoff, 2007; Folk & Remington, 2006; Remington, Folk, & McLean, 2001) or rapid disengagement (Arnott & Pratt, 2002; Theeuwes, Atchley, & Kramer, 2000).

²As required by this measure of trajectory deviation, the mean of the average predicted start and end y-coordinates (see Ludwig & Gilchrist, 2002a) did not differ significantly from zero for either Experiment 1, t(10) = 0.28, p=.789, or Experiment 2, t(9) = 1.57, p=.150.