Asanowicz, D. 1 , Śmigasiewicz, K. 2 & Verleger, R. . 2
1 Institute of Psychology, Jagiellonian University, Krakow, Poland
2 Department of Neurology, University of Lübeck, Lübeck, Germany
In the dual rapid serial visual presentation task, two simultaneous different streams of letters with two targets (T1 & T2) embedded among distractors are rapidly presented in the left and right visual fields. Importantly, T2 is identified markedly better in the left than in the right visual field. In a series of experiments we tested two alternative explanations of the left visual field advantage (LVFA). According to the first one, the LVFA may reflect right hemisphere (RH) dominance in attentional processes. Alternatively, the asymmetry may be caused by left hemisphere (LH) disadvantage, since the LH may be overloaded by rapidly presented letters due to its specialization in processing verbal stimuli. In the first three experiments we gradually reduced distracting stimuli in order to decrease the postulated LH overload. In the next two experiments we employed stimuli for which the RH is specialized, human faces (exp.4) and shapes (exp.5). The LVFA remained consistently present across all experiments, despite the manipulations in procedure and the variation of stimuli. Therefore, the studies seem to falsify the hypothesis of LH overload, and instead suggest that RH superiority, possibly in attentional processing, underlies the LVFA in the dual RSVP task.