Right-left prevalence with task-irrelevant spatial codes.

Abstract In two experiments the relation between handedness and the size of the Simon effect in each visual hemifield has been investigated. Experiment 1 showed that the Simon effect was larger in the right visual hemifield in right-handers and in the left visual hemifield in left-handers, whereas ambidextrous showed a symmetric Simon effect. In Experiment 2, subjects performed the same Simon task as in Experiment 1, but with crossed hands. The right- and left-handers group showed a reversed pattern of results with respect to Experiment 1. We explained this phenomenon as a part of a more general account where perception and action are embedded in a perception-for-action system. In it, an attentional bias originating from the field of operation of the dominant hand would be at the base of the relationship between the asymmetry of the Simon effect and handedness.