Spatial compatibility effects such as the Simon effects are rather robust showing that spatially incompatible mappings between stimulus position and response are not ignored. Previous research used stimulus and response sets varying along both the horizontal and vertical dimension simultaneously. Here, conflicting results were found whether or not the horizontal dimension shows a prevalence over the vertical dimension as shown by differences in the size of Simon effects. These studies used stimulus displays that allowed the simultaneous spatial coding along two different reference frames. However, results were only presented in regard to the horizontal or vertical dimension while mostly ignoring the possible two different kinds of Simon effects within each dimension.
Therefore, the current study used a stimulus display including both, spatial locations varying along different reference frames and dimensions. This ensured that two kinds of Simon effects, i.e. a global (based on the absolute screen position) and a local Simon effect (based on the relative position within the screen’s hemifield) were investigated in the horizontal and vertical dimension. This setup conceptually replicates the study by Rubichi et al, 2005 (Exp. 4) while using the same participants for both dimensions utilizing only their hands as effectors. In contrast to this study, simultaneous global and local Simon effects were observed for either dimension. Further, the global Simon effects were larger than the local ones in either dimension. These results speak against a prevalence effect in regard to stimulus dimension.