面孔加工的结构编码阶段异族效应的加工方式： ERPs研究

实验采用事件相关电位（ERPs）技术,以大学生为被试,运用非洲、欧洲、亚洲三个不同种族的面孔照片,探究异族效应与加工方式的关系。行为实验结果显示,被试对非洲面孔的反应时快于欧洲面孔,且两者均快于亚洲面孔。ERP研究结果显示,亚洲面孔的N170波幅显著小于非洲和欧洲面孔的波幅,后两者的N170波幅没有差异,而且亚洲面孔的倒置效应最大。研究结果说明相对于异族面孔,本族面孔更多地使用构型编码的加工方式,且N170成分表现出右半球优势。     

本族效应的认知神经机制

本族效应是指个体对本族面孔比异族面孔有更好的再认的现象。本族面孔和异族面孔诱发的N170、P200、N200与“DM”效应存在显著差异, 这些脑电成分与本族效应的编码有关, 即对异族面孔编码不充分是本族效应产生的部分原因; “新旧”效应主要从提取角度解释本族效应, 认为提取异族面孔比本族面孔困难。与本族效应有关的主要脑区有梭状回、扣带回与杏仁核等。此外, 丰富的本族面孔知觉经验也会造成本族面孔的右半球优势比异族面孔大。未来研究除了要继续探讨本族效应的某些脑电成分、关注本族效应消失的神经机制以外, 从整合观点探讨本族效应的神经机制也是未来的研究方向。     

提取方式对相继记忆效应的影响

采用学习－测验（自由回忆和再认）研究范式和事件相关电位方法,研究图形的相继记忆效应（Dm效应）。14名大学生作为研究被试,根据其测验成绩将图片分为记住和未记住两类,对相应编码过程的ERPs进行分析。结果表明：⑴行为上,再认的平均击中率显著高于自由回忆;⑵脑电活动上,在刺激出现后400~700ms编码过程中记住项目的ERPs更正于未记住项目的ERPs;同时两种测验方式Dm效应的脑区分布不同,自由回忆主要分布在额区,再认主要分布在中央区和顶区,且在500~600ms自由回忆有左侧优势。这些结果表明,两种提取方式对Dm效应有不同的影响,这一结果预示自由回忆和再认的编码过程可能有不同的神经生理机制。     

婴儿面孔种族效应的发展：经验的作用

面孔种族效应是指个体对本族面孔与他族面孔的加工存在差异,即对本族面孔的识别比他族面孔更快速、更准确,而对他族面孔的分类则优于本族面孔。经验是否以及如何影响面孔种族效应的发展,一直是研究者关注的焦点。近十几年,越来越多的学者对婴儿面孔种族效应进行了研究,已有成果主要涉及两个方面：（1）自然条件下婴儿面孔种族效应的出现与发展,即婴儿在面孔种族偏好、识别与分类以及面孔种族加工方式上的变化;（2）训练对婴儿面孔种族效应的影响。未来应丰富研究模式,增强实验材料的生态性,联合新的神经生理技术手段,进一步揭示婴儿经验对面孔种族效应的作用机制。     

中英文Stroop干扰效应的脑机制

以中国大学生为被试,采用事件相关电位对比研究中英文Stroop干扰效应的脑内时程动态变化。结果发现：两种文字材料都存在反应时的Stroop干扰效应,汉字的干扰效应明显强于英文;被试在完成不同文字材料的字词颜色命名任务时所诱发的ERP成分存在差异,具体为中文Stroop干扰效应表现为在350—550ms内,不一致条件比一致条件诱发一个更负的ERP成分（N450）,主要分布于额中部电极。英文Stroop干扰效应表现为不一致条件比一致条件在250—450ms内诱发一个更正的ERP成分（P300）,主要分布于左侧额顶叶;在450—550ms内诱发一个更负的ERP成分（N500）,主要分布于中后部。研究结果表明语言类型会影响Stroop干扰效应的脑内时程变化。     

内隐面孔记忆的编码机制*

为了探究内隐面孔再认在记忆形成过程中的认知加工状态,该实验以陌生面孔为刺激,采用事件相关电位(ERP)技术,并结合相继记忆(Dm)范式和迫选再认测验,把学习阶段的面孔分为相继记住、相继启动及相继忘记三类,以相继记住与相继启动的 ERP 差异为外显记忆 Dm 效应,以相继启动与相继忘记的差异为内隐记忆的 Dm效应。结果表明,内隐记忆表现为400~500 ms额中央区负走向的 Dm效应,可能反映了额叶皮层对信息的精加工过程,而外显记忆表现为400 ms开始顶区正走向的Dm效应,可能反映了记忆系统对加工后信息的自动登记过程。由此推测,只有经过额叶加工并被内侧颞叶自动登记的信息,随后才能被有意识地提取出来,而未进入内侧颞叶的信息在随后测验中不可能产生有意识地记忆提取现象,但储存的知觉表征可能触发微弱的记忆痕迹,从而产生内隐面孔记忆。     

孤独症谱系障碍患者对种族情境中本异族面孔的眼动模式

本研究采用眼动技术探讨孤独症谱系障碍(ASD)患者对背景中的本异族面孔的加工特点。研究采用2（组别）×2（面孔种族）×3（背景）的混合设计,让16名16-25岁的ASD患者和17名生理年龄匹配的正常人完成变化检测任务,并记录他们的眼动。结果显示：与正常人相比,ASD患者的面孔辨别力更低;他们的眼动呈现更多的面孔-背景眼跳和更多的上下半脸眼跳;两组被试的上下半脸眼跳的次数受到面孔种族以及面孔和背景是否一致的影响。结论：在行为指标上,正常人出现了本族效应,而ASD患者没有出现本族效应;在眼动上,ASD患者呈现与正常人相似的面孔注视时间,但比正常人呈现更多的眼跳。面孔的背景影响了面孔辨别力以及上下半脸眼跳轨迹。     

幼儿面孔加工异族效应的眼动研究

本研究探究国内生活的幼儿在加工面孔时视觉策略上的异族效应。研究选取了在中国本地生活并且没有与异族个体有过直接接触的幼儿和成人, 完成一个学习和再认本族和异族(高加索白人)面孔的实验, 同时眼动仪记录了他们看面孔时的眼动数据。结果发现：国内生活的幼儿和成人在加工面孔时存在视觉策略上的异族效应, 即幼儿和成人均更多地看本族面孔的鼻子和嘴巴区域而更多看异族面孔的眼睛区域。此外, 相对于成人, 幼儿在加工面孔时, 更倾向于看面孔的眼睛部分, 进行局部加工。本研究结果在一定程度上支持了专家—— 新手理论, 对本族面孔更多的视觉经验将我们塑造成自身物种或种族的面孔加工专家, 从而对本族面孔更多地采取以鼻子为中心的整体化视觉加工策略。     

面孔识别中脑电成分N170的研究概述

N170是在面孔刺激呈现后的130-200ms记录到的并在160~170ms时达到峰值的一种脑电负成分。目前, 在N170的研究中存在争议性的问题有：N170反映面孔结构编码还是面孔特征编码; N170是否是面孔特异性成分; 以及N170是否受注意的影响等。这些争议也为N170后续研究指明了方向, 即探讨结构编码和特征编码在诱发N170成分上起着怎样的作用; 比较不同熟悉度的刺激材料所诱发的N170反应差异; 探讨N170成分与识别电位间的关系;采用多研究方法的结合从不同层面深入揭示N170的认知机制。     

面孔-词Stroop范式中的情绪冲突效应研究

为探究面孔-词Stroop范式中的情绪冲突效应,本实验给被试呈现两种时长（150ms或1500ms）的刺激,令其分别完成对面孔-词Stroop范式中的“面孔任务”和“词任务”。结果发现：只有“面孔任务”中出现Stroop效应,产生情绪冲突,而在“词任务”中未出现Stroop效应;当呈现时间为150ms时,情绪词影响情绪面孔加工从而引发个体的情绪冲突,出现Stroop效应;当呈现时间为1500ms时,“面孔任务”中的Stroop效应消失。这提示了呈现时间是影响面孔-词Stroop范式中情绪冲突效应的一个重要因素。     

Domain specificity versus expertise: factors influencing distinct processing of faces

To explore face specificity in visual processing, we compared the role of task-associated strategies and expertise on the N170 event-related potential (ERP) component elicited by human faces with the ERPs elicited by cars, birds, items of furniture, and ape faces. In Experiment 1, participants performed a car monitoring task and an animacy decision task. In Experiment 2, participants monitored human faces while faces of apes were the distracters. Faces elicited an equally conspicuous N170, significantly larger than the ERPs elicited by non-face categories regardless of whether they were ignored or had an equal status with other categories (Experiment 1), or were the targets (in Experiment 2). In contrast, the negative component elicited by cars during the same time range was larger if they were targets than if they were not. Furthermore, unlike the posterior-temporal distribution of the N170, the negative component elicited by cars and its modulation by task were more conspicuous at occipital sites. Faces of apes elicited an N170 that was similar in amplitude to that elicited by the human face targets, albeit peaking 10 ms later. As our participants were not ape experts, this pattern indicates that the N170 is face-specific, but not specie-specific, i.e. it is elicited by particular face features regardless of expertise. Overall, these results demonstrate the domain specificity of the visual mechanism implicated in processing faces, a mechanism which is not influenced by either task or expertise. The processing of other objects is probably accomplished by a more general visual processor, which is sensitive to strategic manipulations and attention.     

“Wanted!” The effects of reward on face recognition: electrophysiological correlates

The aim of the present study was to uncover the temporal dynamics of face recognition as a function of reward. Event-related potentials (ERPs) were recorded during the encoding and the subsequent old/new memory test in response to faces that could be associated with a monetary reward. The behavioral results showed that faces associated with reward at both encoding and retrieval were recognized better than the unrewarded ones. ERP responses highlighted that successful encoding predictive of subsequent memory was greater for faces associated with reward than for faces without reward-driven motivational learning. At retrieval, an early positive-going component was elicited for potentially rewarded faces on frontal regions, while the occipito-temporal N170 component showed priming effects as a function of reward. Later on, larger centro-parietal ERP components, related to recognition memory, were found selectively for reward-associated faces. Remarkably, electrophysiological responses varied in a graded manner, with the largest amplitude yielded by faces with double reward, followed by faces associated with reward only at encoding. Taken together, the present data show that the processing of outcome expectations affects face structural encoding and increases memory efficiency, yielding a robust and sustained modulation over frontal and temporal areas where reward and memory mechanisms operate in conjunction.     

Task‐irrelevant own‐race faces capture attention: Eye‐tracking evidence

To investigate attentional capture by face’s race, the current study recorded saccade latencies of eye movement measurements in an inhibition of return (IOR) task. Compared to Caucasian (other‐race) faces, Chinese (own‐race) faces elicited longer saccade latency. This phenomenon disappeared when faces were inverted. The results indicated that own‐race faces capture attention automatically with high‐level configural processing.     

Implicit effects of emotional contexts: An ERP study

Previous recognition memory experiments have demonstrated that the ERPs elicited by correctly recognized test items differ according to whether the items were encoded in an emotionally arousing or an emotionally neutral context. It is not clear, however, whether these ERP differences depend on the explicit recognition of the items. We addressed this question in the present study by contrasting the ERPs elicited by test items encoded in emotionally negative or emotionally neutral study contexts, according to whether the items were correctly recognized or misclassified as new. Recognized items associated with emotional rather than neutral contexts elicited an early positive-going and a later negative-going effect that resembled the effects reported in prior studies. Relative to unrecognized items encoded in neutral contexts, unrecognized items encoded in emotional contexts elicited a sustained, frontal-maximum, positive-going effect that onset at about 200?ms poststimulus. This effect may reflect an influence of emotional arousal on the neural correlates of implicit memory.     

正性情绪诱导下的自我参照加工：来自ERPs的证据

采用事件相关电位考察正性情绪对自我参照加工程度效应的影响。实验采用图片启动范式, 先呈现情绪图片, 然后再呈现自我参照刺激。实验发现, 在P2上, 中性情绪条件比正性情绪条件激发了更大的波幅, 高自我相关的刺激比其它刺激诱发了更短的P2潜伏期; 在N2上, 高自我相关名字比中等自我相关名字和非自我相关名字诱发了更小的N2的波幅和更长潜伏期; 在P3上, 高自我相关名字比中等自我相关名字和非自我相关名字诱发了更大的P3波幅, 中等自我相关名字比非自我相关名字诱发了更大的P3波幅。实验结果表明, 人类大脑对正性情绪刺激的加工可能是不敏感的。无论在正性情绪启动还是中性启动的影响下, 自我参照加工都能展现出稳定的特征, 而且高自我相关的刺激会得到更为深入和精细的加工, 表现出自我参照加工的程度效应。     

Meaningful processing of meaningless stimuli: the influence of perceptual experience on early visual processing of faces

The N170 is an event-related potential component associated with extrastriate visual mechanisms involved in detecting human faces and leading to their characteristic structural encoding. Consequently the N170 discriminates the processing of stimuli providing physiognomic information from the processing of other, similarly complex, visual patterns. We have used this effect to explore the top-down influence of newly acquired experience on the initial visual categorization of physiognomic stimuli. Schematic faces having the inner components mislocated did not elicit an N170 effect in naive participants. However, after normally configured versions of the schematic faces were exposed, suggesting what the ambiguous patterns represented, the same patterns elicited an N170 effect as conspicuous as that elicited by regular schematic faces. This priming effect, which changed the visual processing of distorted faces in extrastriate regions, could not be explained by post-perceptual decisions. Although accounts based on changes in focal attention, or within-vision constraints could not be categorically rejected, this outcome might suggest cognitive penetrability of early visual categorization.     

The influence of processing objectives on the perception of faces: An ERP study of race and gender perception

In two experiments, event-related potentials were used to examine the effects of attentional focus on the processing of race and gender cues from faces. When faces were still the focal stimuli, the processing of the faces at a level deeper than the social category by requiring a personality judgment resulted in early attention to race and gender, with race effects as early as 120 msec. This time course corresponds closely to those in past studies in which participants explicitly attended to target race and gender (Ito &Urland, 2003). However, a similar processing goal, coupled with a more complex stimulus array, delayed social category effects until 190 msec, in accord with the effects of complexity on visual attention. In addition, the N170 typically linked with structural face encoding was modulated by target race, but not by gender, when faces were perceived in a homogenous context consisting only of faces. This suggests that when basic-level distinctions between faces and nonfaces are irrelevant, the mechanism previously associated only with structural encoding can also be sensitive to features used to differentiate among faces.     

Deficits in early-stage face perception in excessive internet users

Excessive Internet use is associated with a limited ability to communicate effectively socially, which depends largely on the capacity for perception of the human face. We used a passive visual detection paradigm to compare the early stages of the processing of face-related information in young excessive Internet users (EIUs) and healthy normal subjects by analyzing event-related potentials (ERPs) elicited by faces and by nonface stimuli (tables), each presented in the upright and inverted position. The P1 and N170 components of the spectrum of ERPs elicited at occipital-temporal sites by the viewing of faces were larger and peaked sooner than the same ERP components elicited by tables, and inverted faces significantly enhanced and delayed the N170 component. EIUs had a generally smaller P1 component than did normal subjects, whether elicited by faces or by tables, and the N170 effect, or difference in amplitude of the N170 component for faces versus tables, was significantly smaller in the EIUs than in normal subjects. However, the N170 inversion effect, or difference in amplitude of the N170 component elicited by upright versus inverted faces, was similar in the EIUs and normal subjects. These data indicate that EIUs have deficits in the early stage of face-perception processing but may have intact holistic/configural processing of faces. Whether some deeper processes of face perception, such as face memory and face identification, are affected in EIUs needs to be investigated further with more specific procedures.     

Seeing “us vs. them”: Minimal group effects on the neural encoding of faces

Faces are inherently social, but the extent to which social group information affects early face processing remains unknown. To address this issue, we examined cortical activity associated with structural encoding of novel ingroup vs. outgroup faces. Participants were assigned to one of two arbitrarily-defined groups using the minimal group procedure, and event-related potentials (ERPs) were recorded while participants categorized faces of people identified as members of their novel ingroup vs. outgroup. Our analysis focused on the N170 component of the ERP, which peaks 170 ms following face onset and reflects face structural encoding. Ingroup faces elicited larger N170 amplitudes than outgroup faces, suggesting that mere group information affects this initial stage of face perception. These findings show that social categories influence how we “see” faces, thus providing insight into the process through which categorizations may lead to biased intergroup perceptions.