词义与大脑机能一侧化

THE MEANING OF WORDS AND CEREBRAL FUNCTION LATERALIZATION.

在左右两侧视野同时呈现单字词和双字词的条件下,以速示的方法,比较了有听力的被试和聋人被试汉字识别时大脑两半球机能的非对称性。结果表明,有听力的被试对单字词和双字词的识别均表现为右侧视野的优势,而聋人组财表现为方向完全相反的左侧视野的优势。两组被试左侧视野的得分几乎相等,右侧视野的得分则聋人组明显地低于听力正常组。对抽象词和具体词的识别两组被试的同侧大脑半球都没有显示出明显的差别,表明大脑两半球对这两类词的识别可能并没有特定的选择性。因此,用速示的方法所反映出来的可能是在认读加工过程中大脑两半球不同加工机制的差别,与字义可能无关。

The asymmetry of hemispheric function in recognizing Chinese singlecharacters (30 abstract and 30 concreate words) and two-characters (30abstract words) by normal hearing subjects and deaf subjects were compa-red by using tachistoscopic approach. The results indicated that the twogroups had just opposite hemispheric advantage effect when the test wordswere presented simultaneously to the right and left visual field, i. e.,thenormal subjects showed right visual field advantage (left hemisphere) inrecognizing Chinese single characters and two-characters, but the deaf sub-jects showed advantage of the left visual field (right hemisphere). How-ever, the two groups had the same scores in the right hemisphere, never-theless, the deaf subjects had significantly lower scores in the left hemis-phere than that of the normal subjects, which suggested that the absenceof the speech perception impeded severely the normal development of theleft hemisphere function mediated by the phonetic recoding. On the basesof comparison between the left and right hemisphere to recognizing accu-racy of both abstract and concreate words, we found that although the nor-mal hearing group showed left hemisphere superiority for both abstractand concreate words, their ipsilateral hemisphere had the same scores forthese two classes of words, nevertheless, the deaf group showed right he-misphere superionity for abstract words and no difference between the twohemispheres for concreate words, it was the same to these two classes ofwords to recognize in their ipsilateral hemisphere. It suggests that the twohemispheres might not have specific selectivity for both abstract and con-create words, or at least not revealed by this tachistoscopic approach.Our results are consistent with the dual-coding hypothesis in the readingprocessing mechanisms, but speech sound may play an important role indetermining hemisphere superiority action. Therefore, what was reflectedby the tachistoscopic task were the differences of the two hemisphere pro-cessing mechanisms in recognizing Chinese characters, there may not beany relation to the meaning of the words.