School of Psychology, University of Nottingham, Nottingham, UK.
Exp Brain Res. 2022 Oct;240(10):2715-2723. doi: 10.1007/s00221-022-06450-3. Epub 2022 Sep 8.
The grating orientation discrimination task (GOT) is a sensitive and reliable measure of tactile spatial resolution, or acuity. We used the GOT in three experiments to investigate the effects of hand posture and hand visibility on spatial acuity. Participant sex and experimental design were also manipulated. Healthy adult participants received brief touches to their index fingertips of grated, domed objects. Their task was to decide whether the gratings ran 'along' or 'across' their finger. Measures of the smallest grating width for which participants could reliably discriminate between orientations were recorded as threshold. Experiment 1 evaluated the effect of two- versus one-interval discrimination, hand used and participant sex. Experiments 2 and 3 evaluated the effects of hand visibility (visible or covered) and hand posture (in front or to the side). Females were better than males; the two-interval task resulted in lower thresholds than the one-interval task; and left and right hand thresholds were not significantly different. Most importantly, while hand visibility did not have a significant effect on the task, thresholds were affected by hand posture-worse when the hand was oriented to the side of the body than in front. These results replicate previously reported effects of sex (or finger size), but failed to replicate the so-called 'visual enhancement of touch' (VET) effect. We also report a meta-analysis of 27 VET studies, finding a significant effect of 'non-informative' vision on tactile perception. Our novel finding is that hand posture affects tactile acuity.
光栅方位辨别任务（GOT）是一种灵敏可靠的触觉空间分辨率或锐度测量方法。我们在三个实验中使用 GOT 研究了手姿势和手可见性对手的空间锐度的影响。参与者的性别和实验设计也被操纵。健康的成年参与者接受在其食指指尖上短暂触摸带有格栅或凸起物体的实验。他们的任务是决定格栅是“沿着”还是“横跨”他们的手指。参与者能够可靠地区分方向的最小格栅宽度的测量值作为阈值记录下来。实验 1 评估了两种与一种间隔的辨别、使用的手和参与者性别的影响。实验 2 和 3 评估了手可见性（可见或覆盖）和手姿势（在前面或侧面）的影响。女性比男性更好；两间隔任务导致的阈值低于一间隔任务；左右手的阈值没有显著差异。最重要的是，虽然手的可见性对任务没有显著影响，但手的姿势确实会影响阈值——当手位于身体侧面时比位于前面时更差。这些结果复制了先前报道的性别（或手指大小）的影响，但未能复制所谓的“触摸的视觉增强”（VET）效应。我们还报告了对 27 项 VET 研究的荟萃分析，发现“非信息性”视觉对触觉感知有显著影响。我们的新发现是手的姿势会影响触觉锐度。
