Right-Hemisphere Advantage of Target Processing in Rapid Series of Stimuli: On the Roles of Attention, Emotion, and Temporal Order

When capacity of the perceptual system is burdened with processing of preceding target stimuli, chances for rapidly presented information to be consciously perceived are much better in the left than in the right half of the visual field. Aiming at understanding the psychological and neurophysiological mechanisms of this asymmetry, we conclude from previous work in this project that this asymmetry neither reflects some perceptual or capacity advantage of the right hemisphere (which is concerned with the left visual field) nor is induced culturally by learned direction of reading. Rather, the hypothesis crystallized that the asymmetry presumably reflects an advantage of the right hemisphere in directing attention reactively to external relevant stimuli. In this project, positive evidence will be provided for this hypothesis: (1) by means of experimentally manipulating the directing of attention, and (2) neurophysiologically, by tackling the temporo-parietal junction as target zone of interfering magnetic stimulation, and by analyzing right-left asymmetries in spontaneous EEG and in distractor- and target-evoked EEG potentials. Furthermore, (3) it will be investigated whether the visual-field advantage extends from conscious identification to conscious and unconscious emotional responses, and (4) paradoxical effects of rapidly presented targets, seemingly directed backwards in time, will be further investigated and modeled.

In the current project we were trying to analyze how emotional and cognitive processes might interact with each other. Two models of affective and cognitive processing were tested: firstly, “the high and low road” model of LeDoux, and secondly the multiple-waves model of Pessoa & Adolph. In a series of experiments we were combining the dual-stream RSVP task (cognitive processing) with classical conditioning (emotional processing). Results indicate the multiple-waves model as adequate description of cognitive and emotional processing. The right-hemisphere advantage, which was previously observed in the dual-stream RSVP task, appears also when the emotional load is added to the task. It might be seen first as an universal phenomenon, independent of the task and secondly as the right hemisphere advantage in directing attention to salient events, both cognitive and emotional.