书写习惯对数字空间表征SNARC效应的影响

本文设计两个实验,采用大小判断任务,选取读写习惯相反的维、汉大学生为研究对象,探讨两类被试对阿拉伯数字和母语数字空间表征的一致性与差异性。结果发现：（1）维、汉被试均表现出对阿拉伯小数反应左手快于右手,对大数反应右手快于左手,即出现正向SNARC效应;（2）维吾尔族被试表现出对母语小数反应右手快于左手,对大数反应左手快于右手,即对母语数字出现反向SNARC效应;汉族被试表现出对母语小数反应左手快于右手,对大数反应右手快于左手,即对母语数字出现正向SNARC效应。结论：（1）维、汉被试对于阿拉伯数字的SNARC效应存在一致性;（2）维、汉被试母语数字的SNARC效应存在差异性;（3）数字空间对应性与书写习惯是导致结果的重要因素。     

数字的空间特性

当要求被试对数字进行奇偶判断时,左手对小数的反应较快,而右手对大数的反应较快,该现象被称为空间数字反应编码联合效应（SNARC效应）。大量研究证实了SNARC效应的存在,该效应表明人类对数字的加工受空间表征和空间注意的影响。该文系统地回顾了SNARC效应存在及其发生阶段的证据,对比了Simon效应与SNARC效应,最后尝试着从空间注意的角度挖掘数字和空间的本质联     

言语与空间任务指令对数字-空间联结编码的影响

以1～9除5外的阿拉伯数字和汉字标签“左”“右”为实验材料，采用数字奇偶判断任务，探讨任务指令对数字-空间联结编码的影响。结果发现：言语任务指令条件下，词语一致性与物理一致性的交互作用显著，且词语一致和不一致时均未发现空间-数字联合反应编码效应（SNARC），表明言语-空间编码在数字-空间联结中更有优势；空间任务指令条件下，物理一致性主效应显著，且词语一致和不一致时均出现了SNARC效应，表明视觉空间编码更有优势。说明数字-空间联结编码受实验任务指令的影响，被试会根据任务指令设置的情景选择视觉空间编码或言语-空间编码对数字进行空间联结。     

刺激的知觉辨认难度与大脑两半球间的分布式加工

采用半视野速示术将标准刺激在中间视野呈现,比较刺激以不同偏心视角（3.5°,5°和6.5°）在左或右视野同时呈现,以检查不同偏心视角引起比较刺激知觉辨认难度的改变对汉字大写数字奇－偶概念同/异判断任务在大脑两半球间分布式加工的影响。结果显示：随偏心视角的增大正确反应时和错误百分数均显著提高;三种视角条件下左右手的正确反应时均有明显的右视野（左半球）优势;3.5°视角右视野（左半球）呈现时右手反应明显快于左手,5°视角右视野（左半球）与左视野（右半球）呈现时均为右手反应明显快于左手,6.5°视角右视野（左半球）与左视野（右半球）呈现时均为左手反应明显快于右手。这些结果提示：本研究条件下只有比较刺激在6.5°偏心视角呈现时刺激和反应可能出现大脑两半球间分布式加工,3.5°和5°视角呈现时可能为左半球单独加工。6.5°视角刺激呈现的分布加工明显由于大视角呈现时比较刺激辨认难度与注意要求的提高所致。     

词义与大脑机能一侧化

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。     

任务转换对SNARC效应的抑制

采用任务转换范式,要求被试判断呈现数字的大小或奇偶性,考察了任务转换对SNARC效应的影响。结果发现:任务重复组被试对小数字用左手反应更快,对大数字用右手反应更快,任务重复组被试在数字认知加工中出现了经典的SNARC效应。相反,任务转换组被试在数字认知加工中未出现SNARC效应。由此可以推测,任务转换对SNARC效应具有抑制作用。     

亮度对空间-数字反应编码联合效应的影响

本研究探讨亮度对空间-数字反应编码联合效应（Spatial-Numerical Association of Response Codes,简称SNARC效应）的影响及其机制。通过三个实验设计不同的亮度对比水平,要求被试对阿拉伯数字1~9（5除外）进行奇偶判断。实验一将数字亮度设为最高值255时,结果出现了数字的SNARC效应。实验二将数字的亮度值分别设为255和213时,结果仍存在SNARC效应。实验三将亮度值分别设置为213和42时,数字的SNARC效应却消失了。这些结果表明亮度会激活或抑制数字的空间表征,可能与亮度对比值的高低及所消耗认知资源的多少有关。     

贵州少数民族儿童青少年SNARC效应的发展

采用奇偶判断任务,考察二年级至大学阶段贵州民族儿童青少年SNARC效应的发展状况。结果显示：三年级开始出现SNARC效应（包括正确率SNARC效应）;各阶段SNARC效应无显著差异;高、低年级正确率存在显著差异,六年级以后各阶段正确率无显著差异。结论：民族儿童三年级开始形成数字的空间表征。SNARC效应的大小不因年龄而发生变化;被试对奇偶知识的掌握存在发展过程,三年级可能基本理解奇偶信息,六年级后熟练掌握奇偶信息。     

工作记忆负荷、形状干扰对聋人与听力正常人注意捕获影响的眼动研究

通过记录和分析被试的行为和眼动指标,本研究试图探讨不同工作记忆负荷下,形状干扰对聋人与听力正常人不同视野位置上刺激信息捕获注意的异同。研究结果表明：（1）形状干扰刺激虽然没有影响被试视觉加工的认知绩效,但被试的眼动模式会由于工作记忆负荷的改变而改变,高工作记忆负荷时,有形状干扰的注视次数高于无形状干扰。（2）工作记忆负荷、视野位置影响被试视觉加工任务的完成,被试在不同视野位置的加工过程表现出不一致的眼动模式。（3）聋人视觉加工在高工作记忆负荷时存在一定的劣势,但其对不同视野位置的信息加工及形状干扰所产生的注意捕获效应与听力正常人一致。     

异同判断加工中整体和局部特征的作用

采用三种整体局部特征（关系-属性,全局-局部,抽象-具体）图形,要求3组大学生被试完成异同判断任务,以考察异同判断加工中整体和局部特征的作用,探讨异同比较的加工机制。三个实验的结果表明：⑴三种整体特征均可加速同反应,因而不支持同判断加工是整体匹配的观点;⑵存在快同效应,但并不支持同判断的快速加工器对整个刺激加工完成后慢速比较器才开始工作的观点;⑶异反应时随差异特征的增多而减小,从而进一步支持异判断是分析加工、自终止的观点;⑷异反应时随差异特征从上至下、从整体到局部而增加,意味着异判断加工的顺序可能是自上而下、从整体到局部。上述结果支持研究假设：同判断的快速加工器先加工整体特征,然后再和异判断的慢速比较器一起开始加工局部特征。     

Evoked potential and visual half-field evidence for task-dependent cerebral asymmetries in congenitally deaf adults

Evoked potentials to laterally presented stimuli were collected from left and right tempero-parietal sites during performance of two visual half-field tasks, lexical decision, and line orientation discrimination. Reaction time and accuracy data were simultaneously collected. The behavioral data indicated the development of a right field advantage for the lexical decision task as a function of practice. A principal components analysis revealed three independent evoked potential components which displayed task-dependent hemispheric asymmetries. Multiple regression analyses revealed that visual half-field asymmetries in response accuracy were closely related to hemispheric asymmetries on several independent evoked response components. Subject's scores on independent tests of verbal reasoning and spatial relations were also found to be closely related to hemispheric asymmetry on several independent evoked response components. These data support a multidimensional concept of cerebral specialization. They also suggest that visual field asymmetries reflect the confluence of several underlying processes which have independent lateralization distributions across the population. In general, the results underscore the need for further research on the nature of the relationship between cerebral and perceptual asymmetries.     

Interhemispheric communication involving multiple tasks: A study of children with dyslexia

The study investigated whether inefficient interhemispheric communication is involved in developmental dyslexia using multiple tasks. A finger localization task, rhyming judgment task, primed lexical decision task, and a visual half-field presentation paradigm were used. Nineteen dyslexic children (mean age = 13.1 years) were compared with 26 chronological age-matched normal children. Although the dyslexic group demonstrated significantly slower and less accurate performance in all three tasks, there was no significant group difference in term of interhemispheric communication. However, priming effects demonstrated by the dyslexic group (p < .05) further indicate that their reading problems may stem from the word retrieval process from the long term memory.     

Hemispheric processing of lexical information in Chinese character recognition and its relationship to reading performance

Hemispheric predominance has been well documented in the visual perception of alphabetic words. However, the hemispheric processing of lexical information in Chinese character recognition and its relationship to reading performance are far from clear. In the divided visual field paradigm, participants were required to judge the orthography, phonology, or semantics of Chinese characters, which were presented randomly in the left or right visual field. The results showed a right visual field/left hemispheric superiority in the phonological judgment task, but no hemispheric advantage in the orthographic or semantic task was found. In addition, reaction times in the right visual field for phonological and semantic tasks were significantly correlated with the reading test score. These results suggest that both hemispheres involved in the orthographic and semantic processing of Chinese characters, and that the left lateralized phonological processing is important for Chinese fluent reading.     

Hemispheric effects of canonical views of category members with known typicality levels

Is there a preferred hemispheric canonical view of a concept? We investigated this question in a natural superordinate category membership decision task using a hemifield paradigm. Participants had to decide whether or not an image of an object lateralized in the left (LVF) or right (RVF) visual half-field is a member of a predesignated superordinate category. The objects represented high, medium, or low typicality levels, and each object had six different perspective views (front, front-right, front-left, side, back-left, and back-right). The latency responses revealed a significant interaction of Hemi Field X View X Typicality (there wasno hemifield difference in accuracy). The findings confirm the presence of asymmetry in stored concepts in long-term memory and suggest, in addition, a hemispheric canonical view of these concepts, a view strongly related to typicality level.     

Does each hemisphere monitor the ongoing process in the contralateral one?

The present study was conducted to examine hemispheric division of labor in the initial processing and error monitoring in tasks for which hemispheric specialization exists. We used lexical decision as a left hemisphere task and bargraph judgment as a right hemisphere task, and manipulated cognitive load. Participants had to respond to one of two stimuli presented to both visual fields and were instructed to correct their errors. To achieve enough correctable errors, participants were encouraged to respond quickly by using a bonus system. The results showed the classical asymmetry for initial responses in both tasks and reversed asymmetry for corrections in the bargraph task at both load conditions, and in the lexical decision task at the high load condition. The results suggest that each hemisphere monitors the ongoing process in the contralateral one and that the dissociation of initial process and its monitoring grows with load of task.     

Multi-Task Study of the Effects of Task Load and Gender on the Development of Visual Field Asymmetries

This study was designed to examine whether the developmental course of visual hemispheric asymmetry is affected by task load and whether gender differences occur with age. Three experiments were performed according to the additive structure of reaction time: “go/no-go” task, “choice-reaction-time” task, and “category-sort” task. Children in three different age groups (7- to 8-years, 10 years, and 13 year olds) were presented lists of words using a visual half-field procedure. Results revealed that in the go/no-go task (Experiment 1), left hemispheric superiority for processing of word stimuli was evident at all three developmental ages, but no gender differences appeared. However, in the choice-reaction-time task (Experiment 2), and the category-sort task (Experiment 3), left hemispheric superiority was displayed by 7- to 8- and 10-year-old males, but not by 13-year-old males. In contrast, girls did not show the left hemispheric advantage at any of the developmental ages. It was concluded that visual hemispheric asymmetry exists in children at an early age, but the magnitude of asymmetry is dependent on age, gender, and task load.     

Hemispheric Processing of Categorical and Coordinate Spatial Relations in Vision and Visual Imagery

Right-handed subjects participated in a visual half-field experiment using “clock” stimuli. For the Categorical task, subjects indicated whether the long and short hands of a clock were above or below the horizontal midline of the dial. For the Coordinate task, they indicated whether the long and short hands of a clock formed an angle that is more or less than 60°. For both tasks, clock stimuli were either analog clocks (Visual version) or digital clocks from which subjects generated images of analog clocks (Imagery version). The results indicated that for both the Visual and Imagery versions, there was a nonsignificant trend toward a left hemisphere advantage in the Categorical task, whereas there was a significant right hemisphere advantage in the Coordinate task. Implications of the results were discussed from the viewpoints of task factors in hemispheric processing of visual imagery, Kosslyn's (1987, 1994) computational model of vision and visual imagery, and vision/imagery isomorphism.     

Assessment of the relationship of cerebral hemisphere arousal asymmetry to perceptual asymmetry.

This study examined the hypothesis that characteristic individual differences in cerebral hemisphere arousal asymmetry are related to individual differences in perceptual asymmetry observed in verbally based visual half-field tasks. The study used electrophysiological measures of arousal asymmetry rather than behaviorally derived measures (Levy, Heller, Banich, & Burton, 1983). Measures of alpha asymmetry were obtained from 20 right-handed males during a baseline relaxation condition and during a visual half-field version of the lexical decision task. Reaction time measures of perceptual asymmetry were obtained during this task. The results indicated that a basal arousal asymmetry measured at the temporal recording location during the baseline condition was significantly related to individual perceptual asymmetry during the subsequent lexical decision task. This basal arousal asymmetry was relatively stable across different task conditions. A task-related arousal asymmetry measured at the parietal location during the lexical decision task also made a significant contribution in predicting individual perceptual asymmetry. These two measures of individual arousal asymmetry were able to predict 50% of the variance in perceptual asymmetry. The implications of the results for explaining more wide-ranging individual differences in behavioral style and personality are discussed.     

Hemispheric differences in the perception of words and faces in deaf and hearing children

The purpose of this study was to investigate hemispheric functional asymmetry in 18 normal hearing children and 18 congenitally deaf children aged 13-14 years. The task was identification of a visual stimulus (3-letter word or photograph of a face) presented in either the left or right visual field. The children responded by pointing to the target stimulus on a response card which contained four different words or three different faces. The percentage of errors for presentations to the two visual fields were analysed to determine hemispheric dominance. The pattern of hemispheric differences for the hearing children was consistent with that from previous investigations. The results for the deaf children differed from those of the normals. In word perception we observed a right hemisphere advantage and in the face recognition a lack of hemispheric differences. These results point to a lack of auditory experiences which is affecting the functional organization of the two hemispheres. It is suggested that the necessity to make use of visuo-spatial information in the process of communication causes right hemisphere dominance in verbal tasks. This may influence the perception of other visuo-spatial stimuli which may yield a lack of hemispheric asymmetry in face recognition.