No influence of sitting vs. standing on Simon effects

In the today's western world, many humans spend a lot of time in a seated position which is also the most dominant position during cognitive experiments. Studies show different performance in tasks during standing and sitting, resulting in an increased interest in the impact of body position on cognitive performance. The present study directly addressed the influence of body position while sitting or standing during performing a Simon task as a measure of cognitive conflict. In a typical Simon task, participants classify lateral stimuli by a non-spatial feature (e.g. color) while the spatial position is task-irrelevant. Stimulus eccentricity (distance from screen center) varied block-wise with low, medium and high eccentricities. Across two experiments in different settings, at home or in the laboratory, the Simon effects were similar while sitting or standing. Moreover, the stimulus eccentricity did not modulate the Simon effects further. Thus, the study provides evidence highlighting that the performance on cognitive conflict tasks is very much alike while sitting or standing. The study has implications for previous accounts on the role of stimulus-related factors modulating the nature of the Simon effect.