How handedness influences perceptual and attentional processes during rapid serial visual presentation.

Stimulus-driven orienting of visual attention is lateralized to the right hemisphere (RH). This lateralization has been studied in the dual-stream rapid serial visual presentation task (dual RSVP). In this task a second target (T2), hard to discern by being embedded in one of two lateral streams of rapidly changing distractors, is better identified on the left than on the right. This phenomenon is called the left visual field advantage (LVFA). Furthermore, in terms of event related potentials (ERPs), the N2pc component and visual evoked potentials (VEPs) are evoked earlier at the RH than at the left hemisphere (LH). All previous dual RSVP experiments were performed on right-handers. In the present study it was investigated how the LVFA and its neural correlates are modulated by handedness. To that end, the size of the LVFA and ERPs (VEPs and N2pc) were compared between right- and left-handers. VEPs were evoked earlier at the RH than the LH in right-handers but not in left-handers. Besides this effect, handedness modulated neither the size of the LVFA nor T2-evoked N2pc. Thus, the LVFA seems to be independent of handedness. Rather than for lateralization of attention, handedness might be relevant for lateralization of early visual perception processes.