Niechwiej-Szwedo Ewa, Cao Michael, Barnett-Cowan Michael
Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Vision (Basel). 2022 Apr 20;6(2):23. doi: 10.3390/vision6020023.
A prerequisite for efficient prehension is the ability to estimate an object's distance and size. While most studies demonstrate that binocular viewing is associated with a more efficient grasp programming and execution compared to monocular viewing, the factors contributing to this advantage are not fully understood. Here, we examined how binocular vision facilitates grasp scaling using two tasks: prehension and manual size estimation. Participants ( = 30) were asked to either reach and grasp an object or to provide an estimate of an object's size using their thumb and index finger. The objects were cylinders with a diameter of 0.5, 1.0, or 1.5 cm placed at three distances along the midline (40, 42, or 44 cm). Results from a linear regression analysis relating grip aperture to object size revealed that grip scaling during monocular viewing was reduced similarly for both grasping and estimation tasks. Additional analysis revealed that participants adopted a larger safety margin for grasping during monocular compared to binocular viewing, suggesting that monocular depth cues do not provide sufficient information about an object's properties, which consequently leads to a less efficient grasp execution.
高效抓握的一个前提条件是能够估计物体的距离和大小。虽然大多数研究表明，与单眼观察相比，双眼观察与更高效的抓握编程和执行相关，但促成这种优势的因素尚未完全了解。在此，我们使用两项任务研究了双眼视觉如何促进抓握缩放：抓握和手动大小估计。参与者（n = 30）被要求要么伸手去抓一个物体，要么用拇指和食指估计一个物体的大小。物体是直径为0.5、1.0或1.5厘米的圆柱体，沿中线放置在三个距离处（40、42或44厘米）。将握力孔径与物体大小相关的线性回归分析结果显示，在单眼观察期间，抓握和估计任务的抓握缩放都同样降低。进一步分析表明，与双眼观察相比，参与者在单眼抓握时采用了更大的安全余量，这表明单眼深度线索没有提供足够的关于物体属性的信息，从而导致抓握执行效率较低。
