Abstract
Preferential reaching tasks have demonstrated a higher likelihood that right-handed individuals use their preferred hand in contralateral space, and consecutively rate higher comfort levels during manipulation compared to left-handers. The right-sided world hypothesis suggests that the continuous pressure on left-handers to use their non-preferred hand results in a higher comfort level during its use, sometimes resulting in a hand preference switch. The purpose of this study was to further investigate the performance and comfort level of individuals who switched their hand preference, for any reason, or length of time compared to those who have never switched. Five right-handed, six left-handed, and eight individuals who underwent a hand-switch (N = 19, females = 13) were tested using a preferential reaching task. The task required the individuals to pick up and manipulate a tool from one of five positions using their preferred hand. Next, the task was repeated but participants had to use a specific hand, whereby upon completion participants subjectively rated their comfort level. Handedness and hand switching experiences were determined using the Waterloo Handedness Questionnaire and the Hand Preference Change Inventory. Results indicated a main effect of the hand-switched individuals displaying less preferred hand selection than both groups (F (2,15) = 6.547, p =.009). Contrary to the right-sided world hypothesis, left-handed individuals had the highest comfort with the preferred hand and lowest comfort with the non-preferred hand (F (2,15) = 25.478, p <.001). Overall, switch-handed individuals experienced a decreased preference for their dominant hand and did not differ in comfort ratings compared to the other two groups.
