质地密度逐渐变化对触觉识别的作用

研究关于输入、本体感受和输出对表面触觉认知的影响，旨在探索运用触觉识别质地密度逐渐变化的表面时，理论关于表面粗糙度恒定的情况下，主动手指运动产生的信息不影响触觉认知的解释是否仍然成立。实验采用表面质地密度呈正态曲线式逐渐变化，组成正负两组变化方向。正方向变化为表面质点密度向中逐渐增大，与手指触摸运动的加减速方式一致；负方向变化为表面质点密度向中逐渐减小，与手指触摸运动的加减速方式相反；另外包括一个表面密度不变的平面。让被试辨别表面质地密度变化的方向，结果发现被试能够很好地判别表面质地密度变化的方向，但在判别正向变化的表面时显得更准确；当表面密度没有变化时，被试倾向于判别为正向变化。这一发现没有支持表面密度恒定的触觉认知解释模型。与常规直觉相反，研究还发现即时反馈并没有改进触觉识别，反而降低了辨别的正确率。质地密度逐渐变化的触觉识别在变化的大小、准确和自信心方面都显示了不同，但没有发现认知学习作用该触觉任务辨别的过程。基于这些发现，文章讨论了触觉质地感知和有关存在的理论解释模式。

Effect of Density Gradients on Haptic Discrimination

This study was designed to contribute to research on the relative roles and contributions of afference,proprioception,and efference to touch-based(or haptic) texture perception. We sought to determine whether theoretical accounts of roughness constancy,in active and passive perception and across broad velocity ranges,would be supported when spatial density gradients were explored.We created textures with sinusoidal spatial gradients that participants explored with sinusoidal velocity directions: positive gradients resulted in densities that increased in the region where exploration velocities were largest while negative gradients counteracted the velocity increases and decreases with decreases and increases in spatial density,respectively.While these gradients could all be detected reasonably well,we found a slight shift in discriminability in favour of positive gradients and found that surfaces with no gradient at all were more likely to be judged to have a positive gradient.This finding runs counter to the roughness constancy models.Counterintuitively,we found that providing the participants with feedback as to their accuracy had a negative impact on gradients.The spatial gradients were of different magnitudes and in different their accuracy and confidence and we found no evidence of perceptual learning in the task.We consider the data relative to existing models and accounts of haptic texture perception.