Is unimanual handedness related to the action hand or the supporting hand in a bimanual task?


Handedness is considered to be a relatively unique characteristic of humans. Typically, handedness is defined as the preferential use of one hand for most fine unimanual tasks, such as writing, hammering, and using a toothbrush. However, most everyday actions utilize both the preferred and non-preferred hands, with each hand assuming a particular role in the action. More specifically, consider the unimanual task of hammering: while the preferred hand clearly is the "action hand" the non-preferred hand plays a supporting role in stabilizing the nail. Unfortunately, most hand preference questionnaires solely focus on the preferred hand and do not consider the role of the non-preferred hand. As such, we created a Bimanual Hand Preference Questionnaire and compared participants' performance on this new questionnaire to the Waterloo Handedness Questionnaire, a traditional measure of handedness. Fifty undergraduate Wilfrid Laurier University students completed both questionnaires, which assessed both direction and degree of handedness for various actions. Overall, the two measures were found to be significantly correlated. Hand preference as determined by the Waterloo Handedness Questionnaire was strongly positively correlated with the hand used to perform an action and strongly negatively correlated with the hand used for supporting actions. The findings indicate that the Bimanual Hand Preference Questionnaire is a valid tool, measuring a related construct to the Waterloo Handedness Questionnaire. Future research will next examine hand performance measures and how they relate to the Bimanual Hand Preference Questionnaire.

Acknowledgments: Supported by NSERC (PJB)