Résumé
Handedness is typically defined by preferred tool use, which is arguably based on cognitive insights of motor planning mechanisms. Also, there is limited evidence of how hand preference relates to online control processes (e.g., Elliott et al., 1993) and no known evidence of how handedness relates to limb-target regulation processes (Elliott et al., 2010). In contrast, right-handed individuals can suppress a secondary, online limb-target regulation acceleration with their dominant hand when a target shifted 3 cm closer during movement and vision was presented for 20 ms (Loria et al., 2019; Manzone et al., 2018). The present study examined limb-target regulation acceleration suppression with the dominant vs. non-dominant hand in right-handed (n=14) and left-handed (n=9) individuals. Participants reached to a target with either hand, with a target jump on 1/3rd of trials and a 20 ms window of vision presented before peak velocity. Although movement endpoint distributions indicated that both groups significantly suppressed the secondary acceleration with both hands, there were significant asymmetries in temporal costs. Right-handed participants exhibited longer times after peak velocity (TAPV) with the left (M=263 ms, SD=46) vs. the right hand (M=246 ms, SD=43) (p=0.011). In contrast, left-handed participants did not exhibit such a significant TAPV cost (non-dominant: M=240 ms, SD=28 vs. dominant hand: M=233 ms, SD=28) (p=0.27). Notably, at least 43% of participants in each group suppressed the secondary acceleration more efficiently with their non-dominant hand. Thus, definitions of handedness are anchored on tool use and do not extend to online limb-target regulation processes.
