知觉组织影响时序知觉的认知机制:ERP研究的证据

以往研究显示,知觉组织影响时序知觉,采用ERP技术拟探讨知觉组织影响时序知觉的认知机制。采集23名被试完成同时判断任务的脑电数据。行为结果发现,知觉组织影响时序知觉,具体表现为知觉组织条件的同时判断频率显著高于非知觉组织条件。ERPs结果发现,在P1和P2成分上,知觉组织条件与非知觉组织条件引发的波幅没有显著差异; 而在N1成分上,知觉组织条件诱发的N1波幅显著大于非知觉组织条件。这表明,知觉组织对时序知觉的影响可能发生在视觉刺激加工的早期阶段,视觉刺激的知觉组织先于时序信息加工。     

知觉适应对种族融合面孔的种族分类和知觉辨别的影响

面孔加工的种族效应(the other-race effects)指人们对面孔做个体辨别任务时辨别本族面孔的绩效优于辨别他族面孔的绩效, 而做种族分类任务时分类他族面孔的绩效优于分类本族面孔的绩效。本研究通过知觉适应操纵被试对种族两歧(高加索和亚洲)融合面孔的种族知觉, 进而比较被试在两种条件下对同一张融合面孔进行种族分类和知觉辨别的绩效的差异。结果发现, 知觉适应能使被试产生将两歧融合面孔知觉为与原始面孔所属种族相反种族的知觉偏向, 并且, 伴随着这种知觉偏向, 两歧融合面孔的加工出现了他族分类优势和本族辨别优势, 提示社会认知因素对面孔加工的种族效应有重要作用。     

知觉组织对时序知觉的双重影响:同时判断任务的证据

本研究探讨知觉组织对时序知觉的双重影响。实验采用三条线段构成的C形为实验材料,操纵图形朝向和SOA水平(实验1和实验2)、图形颜色(实验3)以及反应限制(实验4),要求被试完成同时判断任务。结果发现,在不同的SOA条件下,图形对向条件的同时判断频率均显著高于图形反向条件(实验1),即使在知觉组织线索弱化时这种现象仍然存在(实验2和实验3),而且知觉组织对时序知觉的影响不是由于被试的反应偏向导致的(实验4)。结果说明知觉组织对时序知觉存在双重影响:当两个刺激同时出现时,知觉组织能够提高时序知觉表现; 而当两个刺激非同时出现时,知觉组织显著降低时序知觉表现。     

短时距知觉中的面积效应

初步探讨了短时距（１─５ｓ）下时距刺激的面积大小和立体框架大小对时距知觉的影响及其成因。结果表明：刺激的面积大小对短时距知觉的影响极其显著;存在两种不同反应类型的被试─－大小依存者与非大小依存者,在不同反应类型的被试中刺激的立体框架大小对短时距知觉的影响不同,刺激的立体框架大小对大小依存者的短时距知觉的影响极其显著,但对非大小依存者的影响不显著。     

判断框架对时序知觉位置启动效应的影响

研究采用包含两种判断框架（判断刺激出现的先后次序）的时序判断任务探讨了决策偏向对时序知觉位置启动效应的影响。实验结果表明,时序知觉中存在着位置启动效应,而且在两个靶刺激出现时间间隔不同时,被试在“哪个靶刺激先出现”和“哪个靶刺激后出现”两种判断框架下的正确率存在显著差异,但在两个靶刺激同时出现时并没有出现显著的判断框架效应。因此,本研究推测时序知觉位置启动效应的作用机制不仅包括知觉增强加工过程,而且也与认知决策有关,这为反应偏向理论提供了新的支持证据。     

疼痛背景下时距知觉的变化

时距知觉指对数百毫秒到数个小时时长的知觉, 是日常生活中许多活动的基础。时距知觉受到相当多因素的影响, 如唤醒、注意、动机等。疼痛是一种多维度的心理及生理现象, 包含有感觉分辨、情绪动机、认知评价三个成分。近期研究证明时距知觉会在疼痛背景下发生改变。疼痛背景下时距知觉的相关研究主要涉及三个方面：(1)健康被试对疼痛面孔的时距知觉; (2)实验室诱发疼痛对健康被试时距知觉的影响; (3)临床疼痛患者的时距知觉变化。探索疼痛背景下时距知觉的变化, 可以为理解疼痛的发生发展机制以及时间知觉的机制提供一个新视角。     

语言表征在颜色类别知觉中的作用

采用同时和继时实验任务,探讨语言表征在颜色类别知觉中的作用.实验一刺激同时呈现,被试表现出类别知觉效应,但效应不受语言干扰影响.实验二刺激间隔呈现,被试表现出类别知觉效应,效应在语言干扰时消失.实验三采用继时任务,没有语言干扰,在刺激呈现间隔(SOA)小于300ms时效应不显著,大于等于300ms时效应显著.研究提示类别知觉效应的机制取决于任务要求和被试无意识的认知策略.在同时任务中效应来自知觉过程本身,在继时任务中效应来自语言编码.继时任务中效应量随SOA变化,说明语言表征由上至下地影响知觉加工,类别知觉是一个动态过程.     

发展性阅读障碍与知觉加工

近年来许多行为实验和神经生理学实验都发现 ,发展性阅读障碍与基本知觉障碍有关。在视觉领域研究者提出了巨细胞障碍假设 ,这种假设认为阅读障碍者视觉神经系统中的巨细胞障碍导致他们对某种类型的视觉刺激加工存在困难 ,进而影响阅读。在听觉领域研究发现阅读障碍者加工快速、系列、短暂呈现的声音刺激存在障碍。研究者认为阅读障碍者加工快速刺激输入障碍反映了普遍的时间知觉障碍。这方面的研究发展非常迅速 ,理论观点非常明确 ,并且直接与内在的神经机制相联系 ,形成了与传统的“语言障碍”理论迥然不同的“知觉障碍”理论。“知觉障碍”理论综合了行为、认知和神经等多个层次的研究 ,反映了神经科学发展所带来的巨大影响和认知加工模块化理论的渐渐衰退。     

刺激前alpha振荡对视知觉的影响

人类对感觉阈限附近的视觉刺激的知觉不总是一致的。为探究这种视知觉不一致的现象及其神经机制, 一些研究者关注刺激前脑内自发alpha神经振荡(8~13 Hz)对视知觉的影响。近年来的研究发现, 刺激前alpha振荡能量的降低能提高被试的探测击中率, 但不能提高知觉精确度; 而刺激前alpha振荡的相位能预测被试能否成功探测刺激。刺激前alpha能量被认为调控了视皮层的基础活动强度; alpha能量的降低反映了皮层基础活动的增强, 进而提高了对较弱刺激的探测率。刺激前alpha相位则被认为调控了皮层兴奋和抑制的时间; 大脑在刺激呈现时的不同状态(兴奋/抑制)决定了最终的知觉结果。     

与恐惧相关的简化刺激在不同知觉负载条件下的注意捕获效应

本研究选用视觉搜索范式,探讨了与恐惧相关的简化刺激在不同知觉负载条件下的注意捕获效应。结果发现:在分心物刺激为清晰的条件下,与恐惧相关的分心物刺激能够优先捕获被试注意,即使分心物刺激在一定程度上被简化,与恐惧相关的简化分心物刺激依然具有加工优先权,并且与恐惧相关的简化刺激在低知觉负载条件下和高知觉负载条件下的注意捕获量并没有显著差异,这一结果表明,与恐惧相关的简化刺激不受知觉负载的限制,能够自动化加工。     

A test of the Sophisticated Guessing Theory of word perception

Under difficult viewing conditions, a letter in a familiar word can be perceived more accurately than the same letter alone or in a string of unrelated letters. Sophisticated Guessing Theory asserts that perception is more accurate when a letter appears in a word because its identity is constrained by the identity of neighboring context letters. Experiment 1 tested the following prediction: A letter in a word should be perceived more accurately in strongly constraining word contexts than in weakly constraining word contexts. No such trend was found using a number of different measures of contextual constraint and perceptual accuracy. Experiment 2 verified that, with the same conditions used in Experiment 1 to test Sophisticated Guessing Theory, a strong perceptual advantage could be obtained for letters in words vs. letters alone or in unrelated-letter strings. Several alternative theories of word perception are discussed. The most attractive asserts that for words an additional higher-level perceptual code is formed that is more resistant to degradation than the code formed for letters.     

色觉疲劳、语义饱和对颜色范畴知觉的即时影响

颜色范畴知觉究竟是语言的还是知觉的, 或两者交互引起的认知冲突所致仍在探究与争议之中。本研究采用色觉疲劳和语义饱和操作分别独立地改变知觉或语义加工, 观察二者对颜色范畴知觉效应的即时影响, 以期探究语言和知觉对颜色范畴的作用。结果显示, 色觉疲劳操作导致范畴间颜色辨别反应时减少, 颜色范畴效应增强。语义饱和操作导致被饱和颜色词所属的范畴内颜色辨别反应时增加, 颜色范畴效应增强。说明单独改变知觉或语义加工能力均能影响CCP效应, 支持了语言标签对比模型, 即语言与知觉的交互作用引起颜色范畴知觉的观点。     

Critical influence of particular experiences in the perception of letters,words, and phrases

Letters are generally easier to identify in regular words or pseudowords than alone or in irregular items. This advantage seems to imply that word perception depends on knowledge of general structure. We found, however, that the perceptual advantage of letters in pseudowords over single letters could be increased by preexposing the pseudowords, or reversed by preexposing the single letters. Similarly, preexposure of words alone or in phrases resulted in a perceptual advantage for whichever display had been experienced. The success of identification also depended on the type of task previously performed on test items, and on the reinstatement of prior processing and perceptual context, rather than on only the test items and task themselves. We concluded that memory preserves information about the details of particular perceptual experiences, and that identification depends critically on the similarity of current demands and processing context to the demands and contexts of particular previous experiences.     

重复启动对时序知觉的影响

在时序判断任务中,重复启动导致被试把启动的靶刺激知觉为先出现的。知觉加工增强观和决策反应偏向观都试图解释其机制,但仍存在争议。本研究采用图形材料,通过三个实验系统考察了重复启动对时序知觉的影响。实验结果显示,启动和指导语都具有显著效应。这说明,重复启动对时序知觉的影响涉及知觉加工和决策水平两个方面。实验还首次发现,在启动的靶刺激先出现时发生了重复启动效应的反转。最后,研究提出了双加工表征匹配调节假说,用以综合解释目前的研究结果     

Letters and words in word identification

Studies by Barron and Henderson (1977) and Johnson (1975) provide evidence that whole words may be the unit of identification in word perception, rather than single letters. Johnson found that words were matched faster than a letter to the first letter in a word. Barron and Henderson found faster matching times for words than for legal non-word items in a letter-matching task. These findings support the interpretation that words are identified before individual letters. If so, a word-frequency effect should be expected. Experiments 1 and 2 tested for word vs. first-letter-in-word differences, as well as for a word-frequency effect in simultaneous and delayed visual matching tasks. In the simultaneous task, first letters in words were matched faster than words. In the delayed task, there was no difference between matching words or matching the first letters in words. With both tasks there was a word-frequency effect for word matches but not for first-letter-in-word matches. In Experiment 3, first-letter matching time was unrelated to word frequency or lexical status, although it did vary with orthographic legality. These results, on the whole, are consistent with a race model in which identifications take place simultaneously at word, letter-cluster, and letter levels, rather than a sequential model in which the whole word is identified before the component letters.     

Isolating visual units in the perception of words and nonwords

In three experiments, reaction times for same-different judgments were obtained for pairs of words, pronounceable nonwords (pseudowords), and unpronounceable nonwords. The stimulus strings were printed either in a single letter case or in one of several mixtures of upper- and lowercase letters. In Experiment 1, the stimuli were common one- and two-syllable words; in Experiment 2, the stimuli included both words and pseudowords; and in Experiment 3, words, pseudowords, and nonwords were used. The functional visual units for each string type were inferred from the effects that the number and placement of letter case transitions had onsame reaction time judgments. The evidence indicated a preference to encode strings in terms of multiletter perceptual units if they are present in the string. The data .also suggested that whole words can be used as functional visual units, although the extent of their use depends on contextual parameters such as knowledge that a word will be presented.     

Subchance perception: Anxious, non-defensive individuals identify subliminally-presented positive words at below-chance levels

People who chronically experience anxiety are biased towards subliminally-presented negative information. Recent research has shown that they may also avoid subliminally-presented positive information. However, these findings are equivocal due to the limitations of previous paradigms and measures. This paper reports two experiments demonstrating that highly anxious, non-defensive individuals exhibit subchance perception when attempting to identify subliminally-presented positive words; that is, they identify such words with accuracy rates that are below chance (guessing). Participants attempted to identify masked positively and negatively valenced words that had been presented briefly (6.4 ms) in a two-alternative forced-choice paradigm. In Experiment 1, persons high in trait anxiety and low in defensiveness identified positive words at below-chance levels and negative words at above-chance levels. No other participant-group’s performance differed from chance. In Experiment 2, persons high in trait anxiety and low in defensiveness again exhibited subchance perception of positive words when responding quickly. This represents the clearest evidence to date that anxious, non-defensive individuals systematically avoid subliminally-presented positive information.     

Syllables and spelling units affect feature integration in words

Three experiments showed that syllables and spelling patterns function as higher order units in word perception. Subjects were required to identify the color of a target letter in briefly presented words composed of different-colored letters. In Experiment 1, subjects incorrectly reported the color of a nontarget letter (conjunction error) more often in one-syllable words containing few spelling units than in two-syllable words containing many spelling units. Experiment 2 showed that subjects made more conjunction errors in one-syllable words than in two-syllable words when the number of spelling patterns was controlled. Experiment 3 showed that conjunction errors decreased as spelling units increased when the number of syllables was held constant. Experiments 1 and 3 also showed that more conjunction errors occurred within syllabic and spelling units than between these units. These findings are discussed in light of previous research on syllable and spelling pattern effects.     

Reading spoken words: orthographic effects in auditory priming

Three experiments examined the involvement of orthography in spoken word processing using a task - unimodal auditory priming with offset overlap - taken to reflect activation of prelexical representations. Two types of prime-target relationship were compared; both involved phonological overlap, but only one had a strong orthographic overlap (e.g., dream-gleam vs. scheme-gleam). In Experiment 1, which used lexical decision, phonological overlap facilitated target responses in comparison with an unrelated condition (e.g., stove-gleam). More importantly, facilitation was modulated by degree of orthographic overlap. Experiment 2 employed the same design as Experiment 1, but with a modified procedure aimed at eliciting swifter responses. Again, the phonological priming effect was sensitive to the degree of orthographic overlap between prime and target. Finally, to test whether this orthographic boost was caused by congruency between response type and valence of the prime-target overlap, Experiment 3 used a pseudoword detection task, in which participants responded "yes" to novel words and "no" to known words. Once again phonological priming was observed, with a significant boost in the orthographic overlap condition. These results indicate a surprising level of orthographic involvement in speech perception, and provide clear evidence for mandatory orthographic activation during spoken word recognition.