Department of Psychological Sciences, Ogden College of Science and Engineering, Western Kentucky University, 1906 College Heights Blvd. #22030, Bowling Green, KY, 42101-2030, USA.
Center for Applied Science in Health and Aging, Western Kentucky University, Bowling Green, KY, 42101-2030, USA.
Sci Rep. 2020 Sep 7;10(1):14690. doi: 10.1038/s41598-020-71894-y.
Seventy-two older and younger adults haptically discriminated the solid shape of natural objects (bell peppers, Capsicum annuum). Plastic copies of the original-sized fruits were used as experimental stimuli, as well as copies that were reduced in size to 1/8th and 1/27th of the original object volumes. If haptic object shape is represented in a part-based manner, then haptic shape discrimination performance should be at least partly size invariant, since changes only in scale do not affect an object's constituent parts. On any given trial, participants sequentially explored two bell pepper replicas and were required to judge whether they possessed the same shape or had different shapes. For some participants, the objects to be discriminated possessed the same size, while for others, the two objects had different sizes. It was found that variations in scale did significantly reduce the participants' haptic sensitivities to shape. Nevertheless, the discrimination performance obtained for large variations in size was no lower than that obtained for smaller variations in size. The results also demonstrated that increases in age modestly affect haptic shape discrimination performance: the d' values of the older participants were 15.5% lower than those of the younger participants.
72 名年长和年轻的成年人通过触觉辨别了自然物体（辣椒，Capsicum annuum）的实体形状。原始大小的水果的塑料复制品被用作实验刺激物，以及体积缩小到原始物体的 1/8 和 1/27 的复制品。如果触觉物体形状是以基于部分的方式表示的，那么触觉形状辨别性能应该至少部分地是大小不变的，因为仅在比例上的变化不会影响物体的组成部分。在任何给定的试验中，参与者依次探索两个辣椒复制品，并被要求判断它们是否具有相同的形状或具有不同的形状。对于一些参与者，要区分的物体具有相同的大小，而对于其他参与者，两个物体具有不同的大小。结果发现，尺度的变化确实显著降低了参与者对形状的触觉敏感度。然而，对于较大的尺寸变化获得的辨别性能并不低于较小的尺寸变化获得的辨别性能。结果还表明，年龄的增加适度影响触觉形状辨别性能：年长参与者的 d'值比年轻参与者低 15.5%。
