One interesting aspect of the attentional repulsion paradigm is that the Vernier probe is primarily presented around the vertical midline (e.g., Pratt & Arnott,
2008; Pratt & Turk-Browne,
2003; Suzuki & Cavanagh,
1997). Visual hemifields are represented in contralateral hemispheres; that is, the cortical representation of visual space is divided by the vertical meridian (for a review, see Wandell, Dumoulin, & Brewer,
2007). Thus, stimuli presented very close to each other but on either side of the vertical midline are represented very far from each other in cortical space. Accordingly, disruptions of attentional and perceptual effects when stimuli are presented close to or straddling the vertical meridian have been reported in a number of studies. For instance, T. Liu, Jiang, Sun, and He (
2009) observed that crowding by a single distractor was less pronounced when target and distractor were presented on opposite sides of the vertical meridian compared to when they were presented in the same hemifield. Pillow and Rubin (
2002) showed that discrimination of shapes induced by illusory contours (Kanizsa figures) was impaired when the relevant inducers appeared in separate hemifields. Further, in a recently published paper, S. Liu, Tse, and Cavanagh (
2018) found that the double-drift illusion, a change in the perceived path of a moving Gabor patch induced by internal drift, was reduced at the vertical meridian when the illusory path would cross or be driven toward it. Moreover, increased reaction times have been described in a cueing paradigm when cue and target were presented in different hemifields (Rizzolatti, Riggio, Dascola, & Umiltá,
1987). Finally, multiple object tracking studies demonstrated higher tracking capacity and less interference when the moving stimuli were separated by the vertical meridian (Alvarez & Cavanagh,
2005; Carlson, Alvarez, & Cavanagh,
2007). In a similar vein, an attention-capturing cue should provoke the largest ARE when presented in the same hemifield as the subsequently presented Vernier stimulus. Surprisingly, such an asymmetry has never been reported. Quite to the contrary, the ARE has been observed to be strongest at the central position when the Vernier lines are presented perfectly aligned and to diminish when the test line is presented slightly away from the midline (DiGiacomo & Pratt,
2012; Pratt & Turk-Browne,
2003).