Abstract
The Tapley-Bryden Dot-Marking Task (TBDM; Tapley & Bryden, 1985) is a group-administered test that has been used to assess hand preference in adults primarily. The test asks participants to "make a dot in each circle following the pattern as quickly as you can" within an allotted time of 20 s. The number of dots marked, and the errors made, are counted for two trials with the preferred hand and the non-preferred hand. The task has generally shown a bimodal distribution of hand performance (McManus, Van Horn, & Bryden, 2016). In the current study, we reanalyzed a large dataset of children and youth, and young adults, collected over the last 10 years from multiple studies. The purpose was to evaluate how age and gender influenced the distribution of the performance of the two hands on the TBDM task. Data were amalgamated across studies, resulting in 274 children (between 4 and 18 years) and 486 young adults (greater than 18 years). Results showed a bimodal distribution was indeed present for those over 18 years; however, no such bimodal distribution was seen for the younger age groups. Different findings were revealed depending on whether raw performance scores of each hand were used (model for PH included both age and gender, but not hand preference (R=.729; F(3, 641) = 242.53, p<.001; model for the NPH hand included, age, gender and hand preference (R=.687; F(3, 641) = 1991.63, p<.001) versus a simple difference score (model included both age and hand preference (R=.188; F(3, 631) = 7.717, p<.001). The results highlight how different scores influence findings and will also be discussed in terms of current theories of hand performance.Acknowledgments: Funded by NSERC