Where does attention go when it moves? Spatial properties and locus of the attentional repulsion effect

Abstract

Reliable effects of spatial attention on perceptual measures have been well documented, yet little is known about how attention affects perception of space per se. The present study examined the effects of involuntary shifts of spatial attention on perceived location using a paradigm developed by S. Suzuki and P. Cavanagh (1997) that produces an attentional repulsion effect (ARE). The ARE refers to the illusory displacement of two vernier lines away from briefly presented cues. In Experiment 1, we show that the magnitude of the ARE depends on cue-target distance, indicating that the effects of attention on perceived location are not uniform across the visual field. Experiments 2 and 3 tested whether repulsion occurs away from cue center of mass or from cue contour. Perceived repulsion always occurred away from the cues' center of mass, regardless of the arrangement of the cue contours relative to the vernier lines. Moreover, the magnitude of the ARE varied with shifts in the position of the cues' center of mass. These experiments suggest that the onset of the cue produces a shift of attention to its center of mass rather than to the salient luminance contours that define it, and that this mechanism underlies the ARE.

Figure 1

Trial sequence for the attentional repulsion effect (ARE), adapted from Suzuki and Cavanagh (1997). Stimuli are not drawn to scale.

Figure 2

(A) Mean repulsion effect for all participants (left) as a function of the distance between the nearest part of the cue contour and the vernier target. (B) The same data for three of the participants. The error bars represent ±1 SE.

Figure 3

Stimuli used in Experiment 2, with each of the three cue conditions and set of five possible vernier positions superimposed above and below fixation. The three cue conditions were completed in separate blocks. Stimuli are drawn to scale.

Figure 4

Percentage of “right” responses as a function of top vernier position for each of the two cue configurations and for each of the three cue shape conditions. The error bars represent ±1 SE.

Figure 5

Stimuli used in Experiment 3, with each of the four cue sizes and vernier lines superimposed and drawn to scale.

Figure 6

Mean repulsion effect for all participants as a function of cue radius and cue center-of-mass to target distance. The error bars represent ±1 SE.