Aiming in adults: sex and laterality effects

The purpose of the study was to twofold: to investigate gender-related differences in the asymmetry of aiming with the preferred and non-preferred hand in right-handed adults, and to examine the effect of the spatial requirements of the task on these asymmetries. The hypothesis was that if cognitive functions are more asymmetrically localised in men than in women, one should observe greater left-right differences on some variables in men than in women. Eleven men and eleven women were required to aim fast and accurately at one of three possible targets under a choice reaction time protocol. Performance and kinematics data were analysed. Results revealed an effect of target location on the left hand advantage in reaction time, and gender-related effects on movement time, accuracy, and on the velocity profiles. Overall, women performed more slowly and accurately than men. This gender-related effect could not be accounted for by differential strategies with regard to speed or accuracy, lending support to the idea that differences exist in the neural mechanisms of movement control between the two genders. Finally, although the results show a hand effect on terminal accuracy in men only, they do not support the hypothesis of a greater asymmetry of movement control in men.