Vaidyanathan Natarajan, Penny Steven, Berniker Max
1Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada.
2Department of Mechanical Engineering, University of Illinois of Chicago, Chicago, Illinois, USA.
J Mot Behav. 2020;52(2):236-248. doi: 10.1080/00222895.2019.1609409. Epub 2019 May 20.
Behavioral studies consistently find that subjects move their hand along straight paths despite considerations that suggest reaches should be curved. Literature on this topic makes it clear that the experimentally displayed feedback influences how subjects reach. Could the standard visual feedback, a displayed cursor, explain the lack of path curvature in experimental results? To address this question, we conducted three experiments to examine reach behavior in the absence of the standard visual feedback. In the first experiment, we found significant increases in curvature as visual feedback was progressively extinguished across groups. A second experiment revealed that practiced reaches became curved after the standard visual feedback was removed. A final experiment found that subjects' reaches made before and after a brief display of visual feedback were similar, indicating a preference for specific curved trajectories. Our results suggest that the consistently straight reaches often observed could be due to a bias to move the displayed cursor straight, which when removed reveal subject-specific preferences for reaches that are often curved.
行为学研究一直发现，尽管有一些因素表明伸手动作应该是弯曲的，但受试者的手却沿着直线轨迹移动。关于这个主题的文献表明，实验中显示的反馈会影响受试者的伸手动作方式。标准的视觉反馈，即显示的光标，能否解释实验结果中缺乏轨迹弯曲的现象呢？为了解决这个问题，我们进行了三项实验，以研究在没有标准视觉反馈的情况下的伸手行为。在第一个实验中，我们发现随着视觉反馈在各实验组中逐渐消失，轨迹弯曲度显著增加。第二个实验表明，在去除标准视觉反馈后，熟练的伸手动作变得弯曲。最后一个实验发现，在短暂显示视觉反馈之前和之后受试者的伸手动作相似，这表明受试者偏好特定的弯曲轨迹。我们的结果表明，经常观察到的始终笔直的伸手动作可能是由于有将显示的光标笔直移动的倾向，当这种倾向消除后，就会揭示出受试者对通常是弯曲的伸手动作的特定偏好。
