Evaluating the origins of the preferred hand and manual performance asymmetries in unimanual and bimanual tasks across the lifespan

偏好用一只手完成大多数单手任务是一个有趣的人类特征。手部偏好的一个值得注意的方面是，某些任务往往比其他任务产生更强的偏好和更多的选择。同样，偏好手优势的大小在很大程度上取决于所研究的任务（McManus，范霍恩& Bryden，2016）。一个经常被引用的解释是，执行特定任务所需的技能程度可能会驱动手的选择，然后允许首选的手变得更擅长那些高技能的任务（Steenhuis & Bryden，1989）。在回顾我们的工作（46，6，31），我们认为，“熟练的行为”可能不足以解释利手。工作仍然是为了确定什么样的肢体/半球系统是专门为肢体选择和性能的能力。 拟议的研究将阐明每个肢体/半球系统的性质是专门为肢体选择和表现能力在单手和双手的任务。重点将放在了解非首选肢体和左撇子的个人，这两者都被忽视了在过去的研究的性能能力。重要的是，这项工作还将研究从儿童到老年人的不同年龄组的肢体选择和表演能力的变化。因此，长期的目标是建立一个运动侧化成熟的寿命模型，更好地解释单手和双手任务中无数相互矛盾的发现。短期目标是检查：a）单手和双手任务中的肢体选择（研究主题D1）; B）单手和双手任务中每只手的相对能力（研究主题D2）;以及c）单手和双手任务中横向偏好和表现的成熟（研究主题D3）。为了进一步梳理每个肢体/大脑半球系统的特性，我们将探索单手和双手任务中的横向偏好和表现; d）左撇子（研究主题D4）; e）运动计划/执行受损的个体（例如自闭症谱系障碍，ADHD）（研究主题D5）。虽然在过去已经研究了运动功能的利手性和偏侧化，但我们对每个肢体/半球系统在肢体选择和表现能力方面的专门功能的理解存在很大的差距。不幸的是，许多研究只包括年轻人或右撇子，因此没有捕捉到横向偏好，选择和表现能力的全貌。拟议的研究将填补当前理论中的几个空白，为研究人员提供有关利手指标的信息，并应用于教育，工业和培训方面。

The preference to perform most unimanual tasks with one hand is an intriguing human characteristic. One notable aspect of hand preference is that certain tasks tend to produce stronger preferences and greater selection of the preferred hand than other tasks. Likewise, the magnitude of the preferred-hand advantage depends heavily on the task examined (McManus, van Horn & Bryden, 2016). One often cited explanation is that the degree of skill required to perform a particular task may drive hand selection, which then allows the preferred hand to become more adept at those highly skilled tasks (Steenhuis & Bryden, 1989). In reviews of our work(46, 6, 31) we have argued that "skilled behaviour" may not adequately explain handedness. Work remains to determine the nature of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities. The proposed research will elucidate the nature of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities in both unimanual and bimanual tasks. An emphasis will be placed on understanding the performance abilities of the non-preferred limb and left-handed individuals, both of which have been overlooked in past research. Importantly this work will also examine changes in limb selection and performance abilities across different age groups, from children to seniors. The long-term objective is thus to create a lifespan model of the maturation of motor lateralization that better explains the myriad of contradictory findings in unimanual and bimanual tasks. Short-term objectives will be to examine: a) limb selection in both unimanual and bimanual tasks (Research Theme D1); b) the relative abilities of each hand in unimanual and bimanual tasks (Research Theme D2); and c) maturation in lateral preference and performance in both unimanual and bimanual tasks (Research Theme D3). To further tease apart the nature of what each limb/hemisphere system is specialized for we will explore lateral preference and performance in both unimanual and bimanual tasks in; d) left handers (Research Theme D4); e) individuals with impaired motor planning/execution (e.g. autism spectrum disorder, ADHD) (Research Theme D5). While handedness and lateralization of motor function have been studied in the past, there are large gaps in our understanding of what each limb/hemisphere system is specialized for with respect to limb selection and performance abilities. Unfortunately, many studies include only young adults or only right-handed individuals, thus not capturing the complete picture of lateral preference, selection, and performance abilities. The proposed research will fill several gaps in current theories, inform researchers regarding the metrics of handedness, and be applied to aspects of education, industry, and training.