Abstract
We measured behavioral and electrophysiological asymmetries in the additional singleton paradigm. Participants searched for a shape singleton and reported the orientation of a line segment inside. On some trials, one of the display elements (the distractor) had a color different from the others. At a behavioral level, the results showed that participants were faster to respond to targets in the lower than in the upper hemifield. Analysis of event-related potentials revealed that an index of attentional selectivity, the N2pc component, was also larger in the lower compared to the upper hemifield. This vertical asymmetry is in line with previous reports of enhanced visual acuity and stronger attentional capture in the lower hemifield when basic visual discrimination tasks were used. We also found that participants were faster to detect targets in the right compared to the left visual hemifield, which is consistent with the suggestion that "local" or high-resolution processing is improved in the right hemifield.
Meeting abstract presented at VSS 2017