Abstract
Handedness is defined by the preferred hand to complete a variety of unimanual tasks, where a plethora of behavioural assessments are currently in use. Traditional measures quantify handedness in terms of preference (e.g., questionnaires) performance (e.g., pegboard tasks) and performance-based preference measures. Here a tool’s position in peripersonal space influences selection of the preferred hand and the presence of a tool, in contrast to an object (e.g., a peg) with ‘no purpose,’ is known to increase selection of the preferred hand. In this study we extended the paradigm involving tools by examining whether a tool’s affordance influences hand selection in peripersonal space. It was hypothesized that use of the preferred hand would increase with age. Sixty-nine right-handers (5- to 11-year-olds and adults) were presented with four tools in three tasks: (1) hammer a nail: hammer, rock, wrench and comb; (2) tighten a screw: screwdriver, knife, dime, and crayon; and (3) dig sand in a bucket: shovel, rake, wooden block, and tweezers. Participants were asked to ‘pick the best tool to complete the task’ until all four tools were selected, where task and tool order were randomized. Children were significantly more inclined to select an object based on location; using the right-hand in right space, and the left-hand in left-space for tool selection and then transferring the tool to their preferred hand to use. In comparison, adults were more inclined to use the same hand to pick-up and use the tool, where performance becomes more adult-like as a function of age.
