Does your dominant hand become less dominant with time? The effects of aging and task complexity on hand selection.

The present article examines the lateralization of hand use throughout the lifespan with an emphasis on aging beyond adulthood. The experimental paradigm utilizes a novel observational method to determine the effects of task complexity, a currently misunderstood factor in hand selection. Current literature is contradictory in that some suggest an increase in motor dominance with age, while more recent work has suggested an approach to ambidexterity. Cross-sectional samples of 80 participants (20 between 2 and 4 years, 20 between 10 and 14 years, 20 between 18 and 25 years, 20 over 65 years) were asked to complete the Waterloo Handedness Questionnaire, Tapley-Bryden Dot Marking Task, and the newly designed Task Complexity Gradient. Contrary to previous suggestions, the current findings suggest neither an increase or decrease in laterality, but that motor dominance remains consistent throughout adulthood. The implications of these findings are discussed in terms of motor dominance throughout the lifespan and the factors that determine hand selection.