Abstract
The current study examines the development of laterality throughout the lifespan, with an emphasis on aging beyond adulthood. The experimental paradigm proposes a measurement tool designed to determine the effects of task complexity, a currently misunderstood factor in hand selection. A cross-sectional sample of 60 participants (10 between 3-4 years, 10 between 10-14 years, 20 between 18-25 years, and 20 over 65 years) were asked to complete the Waterloo Handedness Questionnaire, Tapley-Bryden Dot Marking Task, and a newly created Task Complexity Gradient. This novel task required participants to reach into both ipsilateral and contralateral peripersonal space in order to complete a series of increasingly complex tasks. Although the development of lateralization is well documented throughout childhood and into adulthood, beyond adulthood the relevant literature is contradictory. Prior work has suggested an increase in motor dominance with age, while more recent studies have proposed an approach to ambidexterity. Contrary to both these suggestions, statistical analysis revealed neither an increase nor decrease in laterality with age, but that motor dominance remains consistent throughout later adulthood. The implications of these findings are discussed in terms of motor dominance throughout the lifespan and the task factors that determine hand selection.Acknowledgments: The research described here was funded by a grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) to Pamela J. Bryden, and a grant from the Faculty of Science Students Association (FOSSA) to Spencer E. Gooderham. Further recognition must be extended to Schlegel Villages and the Research Institute for Aging for their continued support.