Introduction: We investigated the effects of increased inter-hemispheric interaction (IHI) on conflict monitoring with focus on Simon effect. According to the information-processing models, there are three stages of processing of decision making: stimulus identification, response selection, and response execution. It has been suggested (cf. Hommel, 1993) that the Simon effect generally refers back to the interference that occurs in the response-selection stage of decision making. Simon task was used in this research as a purest assessment of response conflict ( Hommel, 2011; Kornblum et al, 1990). In this task, participants response to a non-spatial feature of commonly visual stimuli by pressing left and right buttons. Importantly, the location of the stimulus varies randomly and is thus sometime corresponding with the location of the correct response (the compatible condition) and sometimes not (the incompatible condition). As one might expect, performance is better with compatible than with incompatible relationship between stimulus location and response – the Simon effect ( Simon and Small, 1969). We expected that the Simon effect would be smaller if being primed by increased inter-hemispheric interaction (IHI). It has been hypothesized that execution of bilateral eye movement would increase the inter-hemispheric transfer due to alternate activation of right-left saccades. There is strong evidence that saccades eye movements are tightly coupled with attention processes. In this study, we hypothesized that rapidly alternating activation of the two hemispheres that is associated with the series of left–right eye movements boosts the visual attention mechanism and enhance faster reaction (press key) to incompatible stimulus, and this improves performance in Simon interference task. Method: IHI was directly manipulated by central (control group) and bilateral viewing conditions of a 30 s eye movement task (EM). Thirty-four university students participated in this stu
