Abstract
Reliable effects of attention on reaction time and accuracy measures have been well documented, yet little is known about how attention affects one's perception of space. Utilizing the attentional repulsion paradigm developed by Suzuki and Cavanagh (1997), the present study examined the effects of transient involuntary spatial attention on the perception of target position. The attentional repulsion effect (ARE) refers to the illusory displacement of two vernier lines away from the focus of attention. In the first experiment, brief peripheral cues captured observers' attention prior to the presentation of a vernier. Responses indicated perceived vernier offset to be away from the cues, replicating the ARE. Moreover, the magnitude of the ARE depended on cue-target distance, indicating that the effects of attention on perceived target location are not uniform and vary systematically as a function of the proximity of the target to the focus of attention. Experiment 2 was designed to determine whether repulsion occurs away from the cue's center of mass or from the cue contour. Perceived repulsion always occurred away from the cue's center of mass, regardless of the arrangement of the contours relative to the vernier lines. However, presenting the vernier within the contours of the cue reduced the magnitude of the repulsion effect, suggesting that the contextual relationship between the cue and the target plays a role in modulating the effect as well. Finally, Experiment 3 demonstrated that increasing the size of the cue increases the magnitude of the repulsion effect when cue-target distance is held constant. Together, these experiments suggest that the magnitude of the ARE depends jointly on the center of the cue's mass and on whether the target is bounded by the cue contour, though attention to the cue's center of mass is largely responsible for producing the repulsion effect.
This research was supported by a grant from NIH (EY016975) to L.C.R. and by the Undergraduate Swan Research Award (Psychology Dept, UC Berkeley) to A.A.K.