触觉时序知觉手臂交叉效应的性别差异

Gender Differences on Crossed-hands Effect of Tactile Temporal Order Perception

本研究探讨触觉时序知觉的手臂交叉效应是否存在性别差异。通过两个实验在较短和较长的SOA条件下考察男性和女性被试在基于体觉和基于外部空间的触觉时序判断任务中的表现。结果表明,男性与女性被试在基于体觉和基于外部空间的触觉时序判断任务中均存在手臂交义效应,SOA较短时男性被试的手臀交叉效应显著小于女性被试,但在SOA较长的条件下手臂交叉效应没有明显的性别差异。触觉时序知觉手臂交叉效应的性别差异可能与空间知觉能力和生理解剖学因素有关.

Temporal order perception is the successive perception of sensory events, which is influenced by many factors. Studies have shown that when the observers＇hands were crossed over the midline, judgments about the temporal order of two successive tactile stimuli delivered to the left and right hands are less accurate as compared to when the hands were placed in an uncrossed posture. Different theories have been proposed to explain the effect, which focuses on the reference frame involved in the touch representation, but not organic variables. In view of the spatial specific of the crossed-hands effect, and spatial factor proved to be influential on male and female spatial performance, we were interested in the role of gender in crossed-hands effect. The temporal order judgment （TOJ） task is used to investigate whether sex influences the crossed-hands effect or not. Twenty-four healthy undergraduate students as paid volunteers participated in this experiment. Each subject participated in three experimental blocks. For one block of crossed-hand trials, subjects were instructed to respond based on which hand was stimulated first （ somatotopic instructions）. And for another block of crossed-hand trials, subjects were instructed to respond based on which side of the body was stimulated first. And in the uncrossed-hand condition, subjects were instructed to respond based on which hand was stimulated first. The response ways that usually employed in prior studies are difficult to avoid confusion, which influenced spatial relation （ compatibility or incompatibility） between stimuli and response on the temporal order judgment. Therefore, subjects are required to make an oral report in this study. Crossed-hands effect is found in both males and females in tactile TOJ tasks based on somatotopic and spatiotopie frames of reference. This robust and reproducible crossed-hands effect has gender differences when intervals are shorter than 150 ms. Female participants produced larger tactile TOJ crossed-hands deficits compared to male participants, especially when stimuli on the left hand or left side （right hand） came first in tasks that stimuli were identified by different reference frames. According to the previous results that the temporal order judgment reversed when the SOA was shorter than 300 ms, temporal order accuracy in the crossed-hands tactile TOJ task significantly improved when the SOA was long enough. The finding reveals that gender differences disappear in the longer SOA condition. Marked gender differences found at moderately short intervals maybe have something to do with the differences of ability to space perception and physiologicanatomy between males and females.