Fig. 1.

a, b Predictions for the relationship between handedness and drift—example for left-handers (note: the inverse pattern between hands is predicted for right-handers). For both hands, we predicted maximal drift in the habitual action space of the arm, i.e., when the hand was positioned near its shoulder of origin (more details in text). a For the dominant (left) hand, we anticipated a steep drop in drift from position one to four. For the non-dominant (right) hand, we predicted limited spatial modulation of drift. The bottom panels represent a schematic of the action space of the two hands as a function of dominance. c The dominant hand is shown in darker tones as its more frequent use in daily action, was predicted to cause the steeper action-based modulation of drift across space (shown in a). d This is in contrast to the non-dominant hand that has a less defined action space and thus results in limited drift modulation. Pos. 1 shoulder out, pos. 2 shoulder in, pos. 3 midline, pos. 4 x-midline—where the shoulder refers to the shoulder of the corresponding hand’s arm (please see in text for more details)