Department of Sports and Health Science, Daito-Bunka University, Tokyo, Japan.
Hum Mov Sci. 2019 Oct;67:102497. doi: 10.1016/j.humov.2019.102497. Epub 2019 Jul 18.
We over-estimate or under-estimate the size of an object depending its background structure (e.g., the Ebbinghaus illusion). Since deciding and preparing to execute a movement is based on perception, motor performance deteriorates due to the faulty perception of information. Therefore, such cognitive process can be a source of a failure in motor performance, although we feel in control of our performance through conscious cognitive activities. If a movement execution process can avoid distraction by the illusion-deceived conscious process, the effect of the visual illusion on visuomotor performance can be eliminated or attenuated. This study investigated this hypothesis by examining two task performances developed for a target figure inducing the Ebbinghaus size illusion: showing visually perceived size of an object by index finger-thumb aperture (size-matching), and reaching out for the object and pretending to grasp it (pantomimed grasping). In these task performances, the size of the index finger-thumb aperture becomes larger or smaller than the actual size, in accordance with the illusion effect. This study examined whether the size illusion effect can be weakened or eliminated by the dual-task condition where actors' attention to judge the object's size and to produce the aperture size is interrupted. 16 participants performed the size-matching and pantomimed grasping tasks while simultaneously executing a choice reaction task (dual task) or without doing so (single task). Using an optical motion capture system, the size-illusion effect was analyzed in terms of the aperture size, which indicates the visually perceived object size. The illusion effect was attenuated in the dual task condition, compared to it in the single task condition. This suggests that the dual task condition modulated attention focus on the aperture movement and therefore the aperture movement was achieved with less distraction caused by illusory information.
我们对物体大小的估计过高或过低，取决于其背景结构（例如，艾宾浩斯错觉）。由于决策和准备执行动作是基于感知的，因此由于对信息的错误感知，运动表现会恶化。因此，这种认知过程可能是运动表现失败的原因，尽管我们通过有意识的认知活动感觉自己可以控制自己的表现。如果运动执行过程可以避免被错觉欺骗的意识过程分心，那么视觉错觉对运动表现的影响可以被消除或减轻。本研究通过检查两个用于引起艾宾浩斯大小错觉的目标图形的任务表现来验证该假设：通过食指-拇指开口（大小匹配）显示物体的视觉感知大小，以及伸出手去触摸物体并假装抓住它（模仿抓握）。在这些任务表现中，根据错觉效果，食指-拇指开口的大小会变大或变小，大于或小于实际大小。本研究检验了在双重任务条件下，即演员注意力被打断，既要判断物体的大小，又要产生开口大小的情况下，大小错觉效应是否可以减弱或消除。16 名参与者在执行大小匹配和模仿抓握任务的同时执行选择反应任务（双重任务）或不执行任务（单一任务）。使用光学运动捕捉系统，根据指示视觉感知物体大小的开口大小分析大小错觉效应。与单一任务条件相比，双重任务条件下的错觉效应减弱。这表明，双重任务条件调节了对开口运动的注意力焦点，因此开口运动受到较少的错觉信息干扰。
