中文听觉双字词认知中的正字法即时激活效应——来自ERP的证据

目的:探讨中文听觉双字词认知中的正字法即时激活效应.方法:采用事件相关电位(ERP)技术,操纵3种双字词条件(一致性:一致、首字不一致、尾字不一致),选择9个电极,使用时间窗分析技术,以50ms为一个时间窗分析300-350ms以及375-675ms时段的脑电波.结果:对前部脑电波平均波幅进行方差分析发现,三种实验条件在575-625ms时间窗差异显著,而在625-675ms时间窗差异边缘显著.首字不一致和一致条件在575-625ms时间窗差异显著,而在625-675ms时间窗差异边缘显著.结论:在中文听觉双字词认知中可能同样存在正字法即时激活效应.     

语义抽象性对非熟练藏英双语者语言联系的影响

目的:考察语义抽象性对非熟练藏英双语者语言联系的影响。方法:采用跨语言长时重复启动实验范式开展实验。结果:在学习阶段为英文具体词语义判断,测验阶段为藏文具体词词汇判断时,已学词的反应时与正确率与未学词相比均不存在显著差异(反应时,F_(1,31)=2.56,P0.05;正确率,F_(1,131)=1.98,P0.05),不存在跨语言长时重复启动效应;在学习阶段为英文抽象词语义判断,测验阶段为藏文抽象词词汇判断时,对已学词的反应显著快于未学词,且正确率更高,存在跨语言长时重复启动效应(反应时,F_(1,31)=17.58,P0.001;正确率,F_(1,131)=15.58,P0.05)。结论:英文抽象词与其藏文对译词之间存在直接联系,支持词汇联系模型和修正层级模型。     

高功能孤独症成人隐喻语义加工的弱中央统合特点

目的:探究高功能孤独症(HFA)成人深层次的非字面语义加工中是否存在弱中央统合特点及其与隐喻熟悉性的关系。方法:从孤独症康复机构及普通学校选取HFA成人以及智商匹配的正常发育(TD)成人各20人参与行为实验。启动任务以传统隐喻句和新异隐喻句为启动句,以隐喻关系解释词,喻体关联词,无关词及假词为目标词,考察两组受试者对隐喻语义的加工情况。再认任务以启动任务的目标词为主要材料进一步考察两组受试者对启动句的加工深度情况。结果:HFA成人在新异隐喻和传统隐喻启动条件下对喻体关联词加工效率最高,反应时为(960.7±9.7)ms、(747.5±12.8)ms,正确率为94.8%、98.4%;TD成人在新异隐喻和传统隐喻启动条件下对隐喻关系解释词加工效率最高,反应时为(817.4±9.0)ms、(619.5±9.9)ms,正确率为93.3%、98.2%。再认任务中,HFA成人在新异隐喻和传统隐喻条件下对喻体关联词再认效率最高,反应时为(732.2±11.9)ms、(788.8±11.7)ms,正确率为78.9%、81.8%;TD成人在新异隐喻和传统隐喻条件下对隐喻关系解释词再认效率最高,反应时为(694.0±10.8)ms、(696.1±11.2)ms,正确率为76.7%、84.2%。结论:在隐喻等深层语义加工层面,高功能孤独症成人存在弱中央统合的认知加工特点,且在隐喻语义加工中,该特点随句子的熟悉度降低而更加明显。     

厌恶启动后水平空间隐喻加工的时间特征:来自事件相关电位(ERPs)的证据

目的:使用语义启动范式并结合事件相关电位技术,探究个体在道德厌恶启动后水平空间隐喻加工的特征及其神经机制。方法:先呈现启动词(道德厌恶词或非道德厌恶词),再呈现目标词(屏幕左侧词语或屏幕右侧词语),被试需判断目标词能否构成词语。通过比较启动词与目标词的不同组合在脑电指标上的差异来考察其加工特征。结果:正确率结果显示启动词与目标词交互作用显著(F=9.37,P0.05)。脑电结果显示(F=7.18,P0.01),道德厌恶启动后,屏幕左侧呈现目标刺激时诱发的N400波幅[(-4.97±0.60)μV]大于非道德厌恶启动后屏幕左侧呈现刺激时诱发的N400波幅[(-3.83±0.56)μV]。结论:道德厌恶与隐喻着道德概念的水平位置(右侧)语义连接程度更高,与隐喻着不道德概念的水平位置(左侧)语义连接程度更低。个体在道德厌恶启动后,会通过倾向选择隐喻着道德概念的"右侧"水平位置来缓解厌恶感。     

视觉注意捕获的神经相关

目的利用事件相关电位(ERP)时空模式考察视觉注意捕获相关的神经网络活动。方法 15名受试者搜索和按键判定8个视觉项目中的一个形状特异目标,实验条件划分根据是否存在突出颜色分心物,采用配对t检验比较两种条件下的行为绩效和ERP数据。结果有突出分心物的反应时(791.20±62.22)ms显著长于无突出分心物(772.40±53.77)ms:t(14)=4.26,P0.001。ERP的t值统计参数映像提示显著的脑区和时段包括:右侧额顶颞区(140~180 ms)、后枕区和额正中区(220~260 ms)、双侧额区(360~460 ms)。结论突出分心物产生了行为分心效应。先后激活的右腹侧和背侧注意网络共同构成了注意捕获的神经基础。     

大学生对不同情绪词内隐记忆与外显记忆的差异

目的:考察大学生对正性、负性和中性词在内隐记忆和外显记忆上的差异。方法:分别使用真假词判断任务和学习-再认范式考察被试对不同情绪词的内隐和外显记忆。结果:在内隐记忆中,大学生对不同情绪词的反应时存在显著差异(F=6.360,P0.05)。进一步分析发现,对积极词的反应时(573.0±57.9ms)和消极词的反应时(650.3±109.12ms)显著短于对中性词的反应时(671.8±101.0ms),但积极词与消极词的反应时之间差异不显著。在外显记忆中,大学生对不同情绪词的正确率和反应时均存在显著差异(F=7.353,15.000,P0.05)。进一步分析发现,被试对积极词记忆的正确率(67.0%±17.9%)明显高于消极词(46.3%±15.9%)和中性词(50.3%±20.4%),但中性词与消极词的正确率差异不显著。积极词(688.2±129.3 ms)和消极词的反应时(814.5±140.3ms)均低于中性词的反应时(951.8±182.0ms),且积极词的反应时明显低于消极词的反应时。结论:刺激本身所具有的情绪信息会影响个体的记忆,个体对不同情绪词的内隐记忆与外显记忆存在差异。     

精神分裂症语义加工异常及认知功能缺陷

目的:探讨精神分裂症患者词汇语义加工是否存在异常及其认知功能的缺陷情况。方法:招募首都医科大学附属安定医院病房和门诊病人26例及匹配的健康被试26例,实验以2(组别:实验、对照)×2(词汇类别:具体、抽象)×2(语义类别:一致、不一致)的混合设计,两组被试均被要求进行语义迫选任务。结果:反应时:患者组反应时(535.692±99.382) ms不长于对照组(520.887±99.382) ms;相对于具体词汇(520.095±94.098)ms,抽象词汇(536.484±94.051) ms的认知加时间更长,[F(1,50)=6.555,P=0.014,η~2_p=0.116];正确率:患者组的正确率(75.320±5.972)低于对照组(87.291±7.657),[F(1,50)=4.922,P=0.031,η~2_p=0.090];认知功能:除了社会认知维度,两组的差异不具有统计学意义(F=1.661,P=0.203),患者组其他的认知功能分数均低于患者组,且差异均具有统计学意义;患者组反应时与认知功能成负相关,正确率与认知功能成正相关,即认知功能损伤越严重,反应时会越长,正确率也会越低。且在语义不一致条件下,具体词汇的正确率和PANSS的阳性量表分成负相关(r=-0.436,P=0.030)。结论:相较于对照组,精神分裂症患者的词汇的语义加工存在异常,认知功能存在缺陷;且认知功能的损伤和其临床症状学指标相平行。     

职业性别刻板印象激活效应:一项ERP研究（英文）

目的:采用事件相关电位技术考察职业性别刻板印象激活效应。方法:使用语义联想启动范式,以代表"男性"或"女性"的单词为启动刺激,以职业性别刻板印象词为目标刺激,让被试判断启动词和目标词是否一致。结果:行为结果发现对比一致条件,不一致条件下被试的反应时更慢,正确率更低;对比男性启动条件,女性被试在女性启动条件下反应时更快,正确率更高。ERP结果发现,对比一致条件,不一致条件诱发了更大的N400波幅;对比男性启动条件,女性被试在女性启动条件下诱发了更大的P600波幅。结论:这些研究结果可能表明职业性别刻板激活效应是存在的,且支持语义匹配模型,而不是扩散激活模型;女性被试具有内群体偏见效应;职业性别刻板印象激活效应和内群体偏见效应都发生在知觉加工的晚期阶段。     

汉语词汇集合容量及新异性对阈下语义加工的影响

目的:考察汉语词汇概念容量和熟悉性对阈下语义加工的影响。方法:结合Greenwald的回归分析技术,采用阈下启动的方式考察刺激集合容量、材料熟悉性对阈下语义启动效应的影响。结果:不论启动刺激是否出现在目标集合,实验都获得了稳定的语义启动效应;启动集合容量的变化不会影响启动效应的出现。结论:汉语词汇的语义信息在无意识状况下得到了加工,而不是形成了刺激-反应联结。该结果支持激活扩散理论。     

汉语发展性阅读困难儿童复合词加工的事件相关电位研究

目的:探索汉语发展性阅读困难(DD)儿童汉语简体字双字符复合词加工的事件相关电位(ERP)特征。方法:抽取新疆某地区2所小学3～5年级儿童进行筛查,共筛出18例DD儿童,年龄匹配26例正常对照(CA)儿童。使用ERP测量方法,让DD组和CA组儿童识别真词、反向非词和随机非词,比较两组儿童反应时、正确率、P200和N400的差异。结果:行为学结果显示DD组真词、反向非词和随机非词的反应时均长于CA组,正确率均低于CA组(均P<0.01)。ERP结果显示未发现P200效应,但有N400效应。DD组真词、反向非词和随机非词中N400平均振幅差异无统计学意义(P>0.05),但CA组随机非词的N400平均振幅比真词和反向非词的N400平均振幅更负(均P<0.05)。CA组随机非词的N400平均振幅比DD组更负(P<0.05)。结论:汉语发展性阅读困难儿童存在语素意识缺陷,复合词加工与N400有关,发展性阅读困难儿童缺乏N400效应。     

Electrophysiology reveals semantic priming at a short SOA irrespective of depth of prime processing

The otherwise robust behavioral semantic priming effect is reduced to the point of being absent when a letter search has to be performed on the prime word. As a result the automaticity of semantic activation has been called into question. It is unclear, however, in how far automatic processes are even measurable in the letter search priming paradigm as the prime task necessitates a long prime–probe stimulus-onset asynchrony (SOA). In a modified procedure, a short SOA can be realized by delaying the prime task response until after participants have made a lexical decision on the probe. While the absence of lexical decision priming has already been demonstrated in this design it seems premature to draw any definite conclusions from this purely behavioral result since event related potential (ERP) measures have been shown to be a more sensitive index of semantic activation. Using the modified paradigm we thus recorded ERP in addition to lexical decision times. Stimuli were presented at two different SOAs (240 ms vs. 840 ms) and participants performed either a grammatical discrimination (Experiment 1) or a letter search (Experiment 2) on the prime. Irrespective of prime task, the modulation of the N400, the ERP correlate of semantic activation, provided clear-cut evidence of semantic processing at the short SOA. Implications for theories of semantic activation as well as the constraints of the delayed prime task procedure are discussed.     

An ERP study of category priming: evidence of early lexical semantic access

We investigated the effects of lexical semantic access on early components of high-density ERPs. Participants performed five blocks of a standard lexical decision (LD) task in which visually presented words were distinguished from nonwords (pseudowords) matched on word length. A second condition involved a lexical semantic (LS) version, in which the words (e.g., tiger) used in each block were selected from a single category (e.g., animals). ERP results indicated that (1) a main effect of lexicality occurred at 100 ms with P1 amplitude greater for words than for nonwords; (2) a task effect for both words and nonwords was also found in the P1 amplitude (larger for LS); (3) a lexicalityxtask interaction in the N1 amplitude indicated lexical semantic access by 168 ms; (4) semantic facilitation of response time to word-nonword judgment may be largely explained by P1 enhancement. Our findings of an early lexicality effect at 100 ms and of semantic access by 168 ms is in accordance with results of recent ERP and eye movement studies.     

The Effects of Semantic Priming and Word Repetition on Event-Related Potentials

Event-related potentials (ERPs) were recorded during the performance of a lexical decision task, in which a proportion of the words were either semantic associates or repetitions of the preceding word. Reaction times were faster to both the second member of associated pairs (targets) and repeated words, with the latter facilitatory effect being more than twice that of the former. ERPs to the semantic primes were more negative-going than those to targets. This difference peaked around 400–450 ms after stimulus onset. Comparison of unrepeated and repeated words revealed a larger and temporally more extended difference, with a similar scalp topography. The prime-target differences are interpreted as a further example of the sensitivity of the ‘N400’ component of the ERP to semantic relationships between words. The differences between the repetition and priming effects in ERPs are considered equivocal with respect to the view that the associated behavioural effects are caused by different cognitive mechanisms.     

Letter search and relatedness proportion: Further electrophysiological evidence for the automaticity of semantic activation

Automatic semantic activation was recently called a myth when the behavioral semantic priming effect was found to be subject to task demands. Semantic priming effects as measured by lexical decision times are typically reduced to the point of being absent when a letter search has to be performed on the prime word. It seems premature to draw any definite conclusion from this behavioral result as ERP recordings show that the same prime task leaves N400 priming effects unaffected. It is still a matter of debate whether N400 priming effects are generated chiefly by automatic or by cognitively controlled priming processes. In the present study we therefore recorded both lexical decision times and ERPs while we varied the ratio of related to unrelated prime–probe pairs (25% vs. 75% related) and thus manipulated the degree to which controlled mechanisms contribute to the semantic priming effect. Behavioral measures revealed reliable semantic priming effects only when RP was high and the influence of controlled processes hence increased. The modulation of the N400, however, provided clear-cut evidence of semantic processing at both RPs, indicating that semantic activation occurred even when RP was low and the involvement of controlled mechanisms was thus minimal.     

SOA-dependent N400 and P300 semantic priming effects using pseudoword primes and a delayed lexical decision.

In a previous semantic priming study, we found a semantic distance effect on the lexical-decision-related P300 when SOA was short (150 ms) only, but no different RT and N400 priming effects between short and long (700 ms) SOAs. To investigate this further, we separated priming from lexical decision, using a delayed lexical decision in the present study. In the short SOA only, primed targets evoked an early peaking (approximately 480 ms) P300-like component, probably because the subject detected the semantic relationship implicitly. We hypothesize that in tasks requiring an immediate lexical decision, this early P300 and the later lexical decision P300 (approximately 600 ms) are additive. Secondly, we found both a direct and an indirect priming effect for both SOAs for the ERP amplitude of the N400 time window. However the N400 component itself was considerably larger in the long SOA than in the short SOA. We interpreted this finding as an ERP correlate for deeper semantic processing in the long SOA, due to increased attention that was provoked by the use of pseudoword primes. In contrast, in the short SOA, subjects might have used a shallowed semantic processing. N400, P300, and RTs are sensitive to semantic priming-but the modulation patterns are not consistent. This raises the question as to which variable reflects an immediate physiological correlate of semantic priming, and which variable reflects co-occurring processes associated with semantic priming.     

Effects of Inter-Item Lag on Word Repetition: An Event-Related Potential Study

Prior exposure to a word can greatly facilitate performance to subsequent presentations of that word. ERP studies have shown that this facilitation is associated with an attenuation of a negative peak normally occurring around 400 ms poststimulus. Recent studies have interpreted this repetition effect as reflecting either lexical access or episodic memory mechanisms. However, there is now increasing evidence that neither of the above mechanisms alone can fully account for repetition effects. The present experiment recorded ERPs to immediate and delayed word repetition during a lexical decision task in order to investigate the time-course of ERP repetition effects. Immediate repetition was found to produce greater response facilitation than delayed repetition. The ERP waveforms of both immediate and delayed word repetition diverged from that of initial word presentation at approximately 300 ms poststimulus. The waveforms for repeated words separated around 400 ms poststimulus with immediate repetition showing a more rapid resolution of negativity and earlier late positivity than delayed repetition. It is suggested that the negativity may reflect processes involved in the overall activation contributing to word recognition, whereas the late positivity may be related to the repetition of stimulus categorization and decision processes.     

The N400 as a function of the level of processing

In a semantic priming paradigm, the effects of different levels of processing on the N400 were assessed by changing the task demands. In the lexical decision task, subjects had to discriminate between words and nonwords and in the physical task, subjects had to discriminate between uppercase and lowercase letters. The proportion of related versus unrelated word pairs differed between conditions. A lexicality test on reaction times demonstrated that the physical task was performed nonlexically. Moreover, a semantic priming reaction time effect was obtained only in the lexical decision task. The level of processing clearly affected the event-related potentials. An N400 priming effect was only observed in the lexical decision task. In contrast, in the physical task a P300 effect was observed for either related or unrelated targets, depending on their frequency of occurrence. Taken together, the results indicate that an N400 priming effect is only evoked when the task performance induces the semantic aspects of words to become part of an episodic trace of the stimulus event.     

A comparison of the electrophysiological effects of formal and repetition priming

Three experiments investigated the electrophysiological consequences of repetition (e.g., scandal-scandal, buple-buple) and formal (e.g., scan-scandal, bup-buple) priming using words and nonwords. In each experiment, repetition and formal priming resulted in positive-going shifts in the event-related potential (ERP) that onset at approximately 200 ms poststimulus and were initially of similar magnitude. Subsequently, the repetition effect became larger than the formal priming effect. Although the word and nonword formal priming effects and the nonword repetition effects were greatest over midline and right hemisphere sites, the word repetition effects were greatest over the midline. It is suggested that the positive-going shift seen in the repetition and formal priming conditions was a modulation of the well-documented N400 component of the ERP. The topographic differences between the priming effects may have reflected differences in the nature of the representations to which cognitive operations are applied rather than differences in the nature of the operations themselves.     

Semantic priming and stimulus degradation: Implications for the role of the N400 in language processing

Two experiments explored the effects of stimulus degradation on behavioral and event-related potential (ERP) measures of semantic priming. The primary goal was to help elucidate the psychological processes that underlie the N400 component. In both experiments, subjects made speeded lexical decisions to words and pseudowords preceded by either semantically related or unrelated prime words. In one block of trials, the target stimuli were intact, and in a second block they were degraded by removing a random 33% of the elements making up each letter of the target (Experiment 1) or by overlaying a matrix of dots on the target (Experiment 2). In both experiments, subjects responded faster and more accurately to related targets than to unrelated targets (behavioral semantic priming effect), and this priming effect was greater when the target was degraded. However, although the N400 component was larger for unrelated than related targets (ERP semantic priming effect), there was no evidence that this difference was larger in the degraded block of either experiment. These results indicate that the behavioral and ERP measures reported here appear to be tapping into different components of the process(es) involved in semantic priming. The implication of the results for the linguistic processes underlying the N400 are discussed.     

Event-related brain potentials evoked by verbs and nouns in a primed lexical decision task

We investigated whether verbs and nouns evoke comparable behavioral and N400 effects in a primed lexical decision task. Twenty-nine students were tested, 13 in a pilot study in which only response times and error rates were collected and 16 in a study in which ERPs were recorded from 124 scalp electrodes. Stimuli were noun-noun and verb-verb pairs with the targets bearing either a strong, a moderate, or no semantic association to the prime or being a pseudoword. Behavioral data revealed comparable priming effects for both word categories. These proved to be independent from the SOA (250 and 800 ms) and they followed the well-known pattern of decreasing response times and error rates with increasing relatedness between target and prime. ERPs revealed pronounced N400 effects for both word categories with a larger amplitude for noun than for verb pairs. A systematic analysis of topographic differences between noun- and verb-evoked ERPs and N400 effects, respectively, gave no convincing support to the hypothesis that the two word categories activate distinct neuronal networks.