顿悟式组块破解的时间进程：ERP研究

本研究旨在探讨顿悟式组块破解的信息加工机制及神经动态变化。被试完成汉字拆解任务,也即从一个源汉字中移动部件从而得到有效汉字。研究操纵部件之间在空间交错背景下的类别关系：同类（移动部件和剩余部件都是汉字）和异类（移动部件是笔画,剩余部件是汉字）。与此同时记录事件相关电位变化。结果显示,同类条件比异类条件引发了更大的N2波动和减小的LPC波动。早期的N2效应可能提示了组块破解过程中的识别困难,而晚期的LPC效应可能提示了组块破解过程中的知觉转换困难。     

组块紧密性导致组块破解困难：部件类型还是交错关系？

本研究的目的是澄清“组块紧密性为何导致组块破解困难”。研究基于汉字减法任务,也即让被试从一个源汉字中移动一个目标部件从而得到一个新汉字,在三个实验中检验了部件类型和交错关系的作用。结果显示,交错条件比非交错条件解答率更低反应时更长;而部件类型效应则主要体现在非交错条件的反应时指标上。结果提示,组块紧密性导致了组块破解困难,这主要取决于空间交错关系;相对的,部件类型作用较小。     

部件类型还是交错关系信息的习得促进问题解决？

本研究旨在探讨知觉组块中部件类型和空间交错关系信息的学习是否促进问题解决。研究采用学习-测试范式,71名有效被试（女性25名,平均年龄=20.51±2.35岁）先学习解答组块破解问题然后进行测试。研究分别在学习和测试阶段基于组块破解任务操纵了部件类型（汉字水平vs.笔画水平）和空间交错关系（交错vs.非交错）。学习阶段,被试分别在四组中完成组块破解练习;在测试阶段完成所有四组问题。研究发现,对交错关系信息的学习与利用相对于部件类型信息促进了问题解决：在涉及交错信息的测试任务上,涉及交错信息比非交错信息的学习条件解答率更高,反应时更短;反之则不是。然而部件类型则没有发现类似的促进效应。与此同时,交错关系信息的习得需要对任务的重复操作学习：涉及交错关系信息的组块破解学习成绩在不同任务间并不随时间推移而提高,但会随重复学习次数而提高。     

字频影响常用汉字认知速度的实验研究

以熟知汉字的大学生为被试,对影响常用汉字认知速度的因素进行了探索．结果发现：（１）读音反应中存在字频效应,对高频字的认读明显快于低频字,表明字频是影响汉字认知速度的因素之一．（２）未见有笔画数效应,认读汉字不是以笔画为单位而可能是以意义化的组块为加工单位的．作者认为影响汉字认知速度的因素是多重的．     

汉字加工的基本单元:来自笔画数效应和部件数效应的证据

用命名作业和真假字判断作业考察了笔画数和部件数对汉字加工的影响,发现,当部件数保持恒定时,笔画数少的汉字较笔画数多的汉字加工快,这种笔画数效应和字频之间不存在交互作用;当笔画数被控制时,部件数效应也存在,但和字频有交互作用,表现在低频少部件汉字的加工要快于低频多部件汉字的加工,而高频汉字中的部件数效应不显著。实验还发现独体字（只有一个部件）的加工和合体字（部件数大于等于二）的加工有差异。作者认为,汉字的加工要经过笔画、部件和整字三个层次,其中单位部件的笔画数和部件数影响着汉字加工时间     

青少年风险决策的时程加工机制：来自ERP的证据

采用事件相关电位（ERP）研究技术,运用剑桥风险任务的实验范式,考察了青少年风险决策的时程加工机制。行为结果表明,在高、中、低三种不确定性条件下,相对于效价,被试的决策更多的关注概率。脑电结果显示：1）不确定性的主效应在N400上表现显著,高不确定条件和中不确定条件的波幅要明显大于低不确定性条件的波幅,而高不确定条件和中不确定条件的波幅无显著差异;2）与中不确定条件相比,高不确定条件和低不确定条件诱发了一个新异正成分（LPC）,高不确定条件和低不确定条件的波幅要明显大于中不确定性条件的波幅,而高不确定条件和低不确定条件的波幅无显著差异。青少年在风险任务中的决策较多的是选择安全选项,表现出较为明显的风险规避倾向。N400的波幅可能反映了不确定性程度,而LPC的波幅大小可能反映了结果评价准确性程度的高低。     

关于知觉干扰效应的ERP研究

利用ERP技术,采用知觉干扰效应的经典实验范式,首次从神经生理水平上探究知觉干扰效应的内部机制。结果发现,递进条件和标准条件均诱发了P2,P3,N400和晚期正成分LPC。在P2,P3和LPC成分上,标准条件的波幅均显著大于递进条件;在N400成分上,递进条件比标准条件波幅更负,潜伏期更长。此外,对递进条件下靶字各模糊水平（Level 1～Level 5）的ERPs进行比较分析表明,N400成分的波幅在各模糊水平间的差异均不显著。基本支持失匹配理论及词汇自动加工理论。     

不同部件亮度条件下的汉字识别初探

本文采用命名作业法探讨在不同汉字部件亮度条件下的字频效应、笔画数效应及部件在汉字识别中的作用。结果表明 :1在本实验条件下 ,字频效应仍非常明显 ,但没有笔画数效应 ;2在上下型汉字的识别中 ,其上半部的作用比下半部更为重要 ,而对左右型汉字而言 ,其右半部的作用比左半部更为重要 ;3部件亮度条件对命名反应时有显著影响 ,但是否可以称为“部件亮度效应”尚值得进一步研究。     

部件启动对合体汉字字形识别的影响

本实验探索了部件启动对左右型合体汉字字形识别的影响,得到以下结果：（1）启动部件与目标字中左部件同形或相似（少一笔划或多一笔划）,会促进对目标字的字形识另询工,表现出正向启动效应;相反,异形部件对目标字加工有干扰作用,表现为负向启动效应;（2）各种启动刺激类型所产生的启动量随启动刺激呈现时间增长而变化。通过对各种实验条件下,启动量的分析,笔者认为：本实验为汉字相互作用激活模型提供了新的证据。     

情绪汉词的主动遗忘效应:ERP研究

尽管证明人类具有主动遗忘能力的研究比较多,但是,探索情绪汉词主动遗忘效应以及电生理机制的实验却非常少。本研究采用事件相关电位技术、T/NT范式探索情绪汉词主动遗忘效应。实验一(行为研究)的结果显示,在中性和情绪汉词条件下,不回忆组的正确率都显著低于基线组,即得到了主动遗忘效应。同时,情绪汉词的主动遗忘效应量小于中性汉词。实验二(脑电研究)结果显示,在200-300ms,Fz,Cz,Pz电极点,回忆组的P2波幅高于不回忆组。在300-400ms,在Fz,Cz,Pz电极点,不回忆组的N2波幅高于回忆组。N2跟抑制过程高度相关,提示抑制是主动遗忘的一个主要原因。在400-500ms,在Pz电极点,回忆组的LPC波幅高于不回忆组。顶叶LPC跟记忆提取高度相关,提示主动遗忘阻止了回忆,这可能是主动遗忘效应发生的内在机制     

Discrimination and categorization of photographs of natural objects by chimpanzees (Pan troglodytes)

Two experiments assessed the ability of four adult female chimpanzees to categorize natural objects. Chimpanzees were initially trained to match different color photographs of familiar objects from four possible categories. In training, all the comparison stimuli were from the same category in one condition, and from different categories in another condition. For all subjects, training performance was consistently better for the "different category" than for the "same category" trials. Probe trials were shown after training. In probe trials, the sample and positive comparison stimuli were different items from the same category, and the foils were selected from among the three other test categories. Individual performance was above chance in probe trials, suggesting that categorization by chimpanzees may transcend perceptual resemblance. These results were later replicated with novel stimulus items from the same four categories (experiment 2). Altogether, this research demonstrates that chimpanzees grouped perceptually different exemplars within the same category, and further suggests that these animals formed conceptual representations of the categories. Accepted after revision: 10 August 2001 Electronic Publication     

特质自我控制个体在多源干扰任务下的认知神经机制

本研究采用事件相关电位技术(ERPs)结合多源干扰任务(MSIT)范式来探讨特质自我控制个体的认知神经机制。考察了高、低自我控制者各26名在MSIT任务上的差异。结果：高自我控制者的反应时显著长于低自我控制者。在MSIT冲突条件下,高自我控制者的N2和P3(LPC)波幅比无冲突条件更大。结论：高自我控制者较低自我控制者处理冲突干扰更慢,需要的注意资源较多,激活前额叶中部脑区。     

Directed forgetting for categorised pictures: recognition memory for perceptual details versus gist

ABSTRACT

Item-based directed forgetting (DF) was tested using 2-alternative forced-choice recognition to examine the effects of forgetting instructions on memory for perceptual detail and gist of categorised pictures of scenes and objects in three experiments. When the distractor is from the same category as the target (exemplar test condition), discrimination must be based on memory for perceptual details, whereas recognition can be based on gist or general category information when the distractor is from a novel category (novel test condition). Recognition accuracy was greater for Remember-cued than Forget-cued pictures when discrimination must be based on perceptual details in the exemplar test condition but not when discrimination could be based on gist in the novel test condition. Accuracy in scene and object recognition is greater for gist than for perceptual details, and DF instructions serve to reduce recognition memory based on perceptual details.     

知觉加工中存在颜色类别知觉效应的证据

对于颜色的辨别具有类别知觉效应：类间两种颜色的辨别能力比同等颜色空间距离的类内两种颜色的辨别能力更高。对于类别知觉效应的产生机制存在两种观点：知觉特性假设、语言标签假设。以往的研究范式由于实验任务涉及到工作记忆成分,被试在完成任务时会自动地对颜色命名以利于记忆,因此所得证据大多支持语言标签假设,而对知觉特性假设的支持证据则很少。本文利用目标觉察范式最大限度去掉了工作记忆成分,通过测量被试辨别两种颜色的反应时,得到了类别知觉效应。并通过语言干扰任务进一步证实在该实验范式下类别知觉效应与语言的无关性。从而,为知觉特性假设提供了证据     

不同掩蔽材料对阅读知觉广度的影响

采用移动窗口技术,探讨了不同掩蔽材料对中文阅读知觉广度的影响,结果表明：（1）相对于“※”掩蔽,文字掩蔽条件下的阅读效率更低、平均注视时间更长、眼跳幅度更小。（2）“※”掩蔽下被试的知觉广度为注视字左侧1个字,右侧2－3个字;文字掩蔽下被试的知觉广度为注视字左侧1个字,右侧3－4个字。综合上述结果,文字掩蔽材料可以比“※”掩蔽材料获得更大的知觉广度,但阅读效率更低。在中文阅读中,文字掩蔽材料更适合探讨阅读知觉广度     

Perceptual and semantic sources of category-specific effects: event-related potentials during picture and word categorization

In two experiments the effect of object category on event-related potentials (ERPs) was assessed while subjects performed superordinate categorizations with pictures and words referring to objects from natural (e.g., animal) and artifactual (e.g., tool) categories. First, a category probe was shown that was presented as name in Experiment 1 and as picture in Experiment 2. Thereafter, the target stimulus was displayed. In both experiments, analyses of the ERPs to the targets revealed effects of category at about 160 msec after target onset in the pictorial modality, which can be attributed to category-specific differences in perceptual processing. Later, between about 300-500 msec, natural and artifactual categories elicited similar ERP effects across target and category modalities. These findings suggest that perceptual as well as semantic sources contribute to category-specific effects. They support the view that semantic knowledge associated with different categories is represented in multiple subsystems that are similarly accessed by pictures and words.     

Inferior Frontal Regions Underlie the Perception of Phonetic Category Invariance

ABSTRACT— The problem of mapping differing sensory stimuli onto a common category is fundamental to human cognition. Listeners perceive stable phonetic categories despite many sources of acoustic variability. What are the neural mechanisms that underlie this perceptual stability? In this functional magnetic resonance imaging study, a short-interval habituation paradigm was used to investigate neural sensitivity to acoustic changes within and between phonetic categories. A region in the left inferior frontal sulcus showed a pattern of activation consistent with phonetic invariance: insensitivity to acoustic changes within a phonetic category and sensitivity to changes between phonetic categories. Left superior temporal regions, in contrast, showed graded sensitivity to both within- and between-category changes. These results suggest that perceptual insensitivity to changes within a phonetic category may arise from decision-related mechanisms in the left prefrontal cortex and add to a growing body of literature suggesting that the inferior prefrontal cortex plays a domain-general role in computing category representations.     

A conflict-based model of color categorical perception: evidence from a priming study

Categorical perception (CP) of color manifests as faster or more accurate discrimination of two shades of color that straddle a category boundary (e.g., one blue and one green) than of two shades from within the same category (e.g., two different shades of green), even when the differences between the pairs of colors are equated according to some objective metric. The results of two experiments provide new evidence for a conflict-based account of this effect, in which CP is caused by competition between visual and verbal/categorical codes on within-category trials. According to this view, conflict arises because the verbal code indicates that the two colors are the same, whereas the visual code indicates that they are different. In Experiment 1, two shades from the same color category were discriminated significantly faster when the previous trial also comprised a pair of within-category colors than when the previous trial comprised a pair from two different color categories. Under the former circumstances, the CP effect disappeared. According to the conflict-based model, response conflict between visual and categorical codes during discrimination of within-category pairs produced an adjustment of cognitive control that reduced the weight given to the categorical code relative to the visual code on the subsequent trial. Consequently, responses on within-category trials were facilitated, and CP effects were reduced. The effectiveness of this conflict-based account was evaluated in comparison with an alternative view that CP reflects temporary warping of perceptual space at the boundaries between color categories.