Abstract
Left- and right-handers show stronger end-state comfort for the right-hand compared to the left-hand; therefore left-hemisphere dominance for motor planning has been suggested, regardless of hand preference (Janssen et al., 2011). This study aimed to assess hand selection during unimanual and bimanual tasks designed to analyze motor planning via end-state comfort. Typically-developing children (n = 92) and adults (n = 20) completed this study; 94 right- and 18 left-handers. Participants were asked to pick-up a cup and pour a glass of water and pick-up a cup and pass it to the research to pour a glass of water. Cup placement altered between right side up and inverted. The hand used to pick-up the cup was recorded using a video camera. Results revealed preferred hand selection to manipulate the pitcher and non-preferred hand selection to pick-up the cup; suggesting the pitcher requires the active, manipulating hand, while the cup has a more passive, supporting role. When only the cup was manipulated, preferred hand selection dominated. That said, regardless of the task, when manipulating the inverted cup, dominance in preferred hand-selection was further highlighted. Interestingly, left-handers showed an increase in right-hand selection when manipulating the inverted cup. Results will be discussed in light of current theories of motor control and motor planning involved in the development of hand preference.Acknowledgments: Research Support: Natural Sciences and Engineering Research Council of Canada (P.J.B)