ABSTRACT

The left hemisphere is known to be generally predominant in verbal processing and the right hemisphere in non-verbal processing. We studied whether verbal and non-verbal lateralization is present in haptics by comparing discrimination performance between letters and nonsense shapes. We addressed stimulus complexity by introducing lower case letters, which are verbally identical with upper case letters but have a more complex shape. The participants performed a same-different haptic discrimination task for upper and lower case letters and nonsense shapes with the left and right hand separately. We used signal detection theory to determine discriminability (d′), criterion (c) and we measured reaction times. Discrimination was better for the left hand for nonsense shapes, close to significantly better for the right hand for upper case letters and with no difference between the hands for lower case letters. For lower case letters, right hand showed a strong bias to respond “different”, while the left hand showed faster reaction times. Our results are in agreement with the right lateralization for non-verbal material. Complexity of the verbal shape is important in haptics as the lower case letters seem to be processed as less verbal and more as spatial shapes than the upper case letters.

摘要

众所周知，左半球通常在语言处理中占主导地位，而右半球在非语言处理中则占主导地位。通过比较字母和无意义形状之间的辨别性能，我们研究了触觉中是否存在言语和非言语偏侧化。我们通过引入小写字母解决了刺激的复杂性，小写字母在语言上与大写字母相同，但形状更复杂。参与者分别用左手和右手分别对大小写字母和无意义的形状执行相同的触觉识别任务。我们使用信号检测理论来确定可分辨性（d'），标准（c），并测量了反应时间。对于废话形状，左手的辨别效果更好，大写字母的右手几乎更好，小写字母的手之间没有区别。对于小写字母，右手显示出对“不同”的强烈偏见，而左手显示出更快的反应时间。我们的结果与非语言材料正确的侧向化一致。言语形状的复杂性在触觉中很重要，因为与大写字母相比，小写字母似乎被处理得少了语言，却被处理成空间形状。