Neuroscience Research Australia, Sydney, New South Wales, Australia.
University of New South Wales, Sydney, New South Wales, Australia.
PLoS One. 2019 Jan 17;14(1):e0210911. doi: 10.1371/journal.pone.0210911. eCollection 2019.
Previous studies revealed that healthy individuals consistently misjudge the size and shape of their hidden hand during a localisation task. Specifically, they overestimate the width of their hand and underestimate the length of their fingers. This would also imply that the same individuals misjudge the actual location of at least some parts of their hand during the task. Therefore, the primary aim of the current study was to determine whether healthy individuals could accurately locate the actual position of their hand when hidden from view, and whether accuracy depends on the type of localisation task used, the orientation of the hidden hand, and whether the left or right hand is tested. Sixteen healthy right-handed participants performed a hand localisation task that involved both pointing to and verbally indicating the perceived position of landmarks on their hidden hand. Hand position was consistently misjudged as closer to the wrist (proximal bias) and, to a lesser extent, away from the thumb (ulnar bias). The magnitude of these biases depended on the localisation task (pointing vs. verbal), the orientation of the hand (straight vs. rotated), and the hand tested (left vs. right). Furthermore, the proximal location bias increased in size as the duration of the experiment increased, while the magnitude of ulnar bias remained stable through the experiment. Finally, the resultant maps of perceived hand location appear to replicate the previously reported overestimation of hand width and underestimation of finger length. Once again, the magnitude of these distortions is dependent on the task, orientation, and hand tested. These findings underscore the need to control and standardise each component of the hand localisation task in future studies.
先前的研究表明，健康个体在进行手部定位任务时，会持续错误判断隐藏手的大小和形状。具体来说，他们会高估手的宽度，低估手指的长度。这也意味着，在任务进行过程中，同一个体至少会对手部的某些部位的实际位置产生错误判断。因此，本研究的主要目的是确定健康个体在隐藏手部时，是否能够准确判断手部的实际位置，以及准确性是否取决于所使用的手部定位任务类型、隐藏手的朝向，以及测试的是左手还是右手。16 名健康的右利手参与者完成了一项手部定位任务，该任务既涉及指向，也涉及口头指示隐藏手上的标记点位置。手部位置被持续错误判断为更靠近手腕（近端偏差），并且在较小程度上远离拇指（尺侧偏差）。这些偏差的大小取决于定位任务（指向与口头指示）、手部的朝向（伸直与旋转）以及测试的手（左手与右手）。此外，近端位置偏差的大小随着实验持续时间的增加而增大，而尺侧偏差的大小在实验过程中保持稳定。最后，感知到手部位置的结果图谱似乎再现了先前报道的对手部宽度的高估和手指长度的低估。这些扭曲的程度再次取决于任务、朝向和测试的手。这些发现强调了在未来研究中需要对手部定位任务的每个组成部分进行控制和标准化。
