Abstract
Visual search for a modulating target in a modulating array is much easier when synchronized with an auditory transient. Here we show an asymmetry in synchrony-driven search efficiency across the visual field. Participants viewed a ring of 19 luminance-modulating discs while hearing a modulating tone. The modulating discs had unique temporal phases (–380 to +380 ms; 40 ms steps), with one synchronized to the tone. Participants did a speeded visual search for the synchronized disc, with modulations (auditory and visual) both sinusoidal or both square at 1.3 Hz. Target position was randomized and spatial distributions of search efficiency were compiled. Results show that sine modulations did not facilitate search (chance performance at all target phases), but square-wave modulations did: the target (phase = 0 ms) was frequently chosen, with tight error distributions (~120 ms wide) around zero-phase lag. Spatially, visual search varied over the visual field: error distributions were more tightly tuned temporally on the right side, especially the upper-right quadrant. These results show that synchrony-driven visual search: (i) requires synchronized transient signals, (ii) has a narrow integration window (±60 ms), and (iii) is spatially biased to the right visual field, suggesting a hemisphereic specialization for synchrony-driven visual search.
Meeting abstract presented at VSS 2013