情绪面孔的意识神经相关物及其无意识自动加工：来自事件相关电位的证据

意识的神经相关物尚有争议, 且个体能否无意识自动检测视觉环境变化尚不清楚。本研究采用非注意视盲范式操控视觉意识, 并引入具有社会信息的情绪面孔, 探讨意识的神经相关物以及视觉意识与自动检测变化机制的关系。在A阶段, 部分被试对任务无关的情绪面孔处于无意识水平; 在B阶段, 所有被试对任务无关的情绪面孔处于意识水平; 在C阶段, 所有被试对任务相关的情绪面孔处于意识水平。结果显示, 任务无关的情绪面孔的意识过程诱发视觉意识负波(visual awareness negativity, VAN)、晚期正成分(late positivity, LP)和晚期枕区正成分(late occipital positivity, LOP)。此外, 无意识的情绪面孔能诱发视觉失匹配负波(visual mismatch negativity, vMMN), 且其幅值不受意识影响, 但是受任务相关性调制。这些结果提示对情绪面孔的视觉意识在不同的时间进程上有不同的ERP指标——VAN反映早期知觉经验, 而LP和LOP反映晚期意识过程, 而且面孔情绪信息的自动加工独立于视觉意识, 但是受视觉注意调制。     

Fast face detection using a unified architecture for unconstrained and infrared face images

Human face detection along with its localization is a difficult task when the face is presented in the cluttered scene in an unconstrained scenario that might be with arbitrary pose variations, occlusions, random backgrounds and infrared (IR) environment. This paper proposes a novel face detection method which can address some of these issues and challenges quite successfully during face detection in unconstrained as well as infrared environments. It makes use of Fast Successive Mean Quantization Transform (FastSMQT) features for image enhancement and feature representation to deal with illumination and sensor insensitiveness. A split up Sparse Network of Winnows (SNoW) with Winnow updating rule is then exploited to speed up the original SNoW classifier. Finally, the features and classifiers are combined together with skin detection algorithm for face detection in crowd image and head orientation correction of near infrared faces. The proposed face detector is robust in handling pose, occlusion, illumination, blur and low image resolution. The experiment is performed on six challenging and publicly available databases, viz. BIOID, LFW, FDDB, UFI, WIDER FACE and IIT Delhi near infrared. The experimental results depict that the proposed method outperforms traditional as well as some advanced methods in detecting unconstrained and infrared faces under challenging situations.     

背景性质对7-10岁自闭症谱系障碍儿童面孔搜索与加工的作用

为了考察背景性质对ASD者搜索面孔的影响,设计两个眼动实验任务,要求14名7~10岁ASD儿童和20名同年龄正常儿童观看图片。实验一采用将面孔嵌入风景图片中引起语义不一致的刺激;实验二采用含有面孔的无意义背景乱序图片刺激。结果发现：（1）面孔与背景语义不一致并不能促进ASD儿童对面孔的搜索;（2）乱序背景对ASD儿童面孔搜索与加工没有产生干扰作用,但使正常儿童的搜索时间变长;（3）一旦觉察到面孔后,ASD儿童对面孔的注视时间少于正常儿童。表明正常儿童对面孔的搜索与加工受背景性质的影响,而ASD儿童不受背景性质的影响;一旦发现面孔,ASD儿童的注意维持较短,但面孔加工模式与正常儿童相似。     

Delayed reconfiguration of a non-emotional task set through reactivation of an emotional task set in task switching: an ageing study

ABSTRACT

In our everyday life, we frequently switch between different tasks, a faculty that changes with age. However, it is still not understood how emotion impacts on age-related changes in task switching. Using faces with emotional and neutral expressions, Experiment 1 investigated younger (n?=?29; 18–38 years old) and older adults’ (n?=?32; 61–80 years old) ability to switch between an emotional and a non-emotional task (i.e. responding to the face's expression vs. age). In Experiment 2, younger and older adults also viewed emotional and neutral faces, but switched between two non-emotional tasks (i.e. responding to the face's age vs. gender). Data from Experiment 1 demonstrated that switching from an emotional to a non-emotional task was slower when the expression of the new face was emotional rather than neutral. This impairment was observed in both age groups. In contrast, Experiment 2 revealed that neither younger nor older adults were affected by block-wise irrelevant emotion when switching between two non-emotional tasks. Overall, the findings suggest that task-irrelevant emotion can impair task switching through reactivation of the competing emotional task set. They also suggest that this effect and the ability to shield task-switching performance from block-wise irrelevant emotion are preserved in ageing.     

Exogenous attention to angry faces in social anxiety: A perceptual accuracy approach

We investigated the interaction between endogenous and exogenous attention for the processing of emotional stimuli in individuals with high social anxiety using accuracy rates. Following the presentation of an endogenous cue at the centre, exogenous cues (i.e., angry and neutral faces) were presented at peripheral locations. Subsequently, non-emotional masked targets were presented, and the participants were instructed to discriminate between the targets. With respect to exogenous attention, high socially anxious people exhibited higher accuracy when the angry face and target appeared on the same side than when they appeared on different sides, whereas low socially anxious people did not exhibit such effects. On the other hand, different abilities of endogenous attention were not observed between high and low socially anxious people. These results suggest that exogenous attention is biased towards threat in high socially anxious people.     

Investigation of effects of face rotation on race processing: An ERPs study

Recent ERP research has indicated that the processing of faces of other races (OR) and same race (SR) as the perceiver differs at the perceptual level, more precisely for the N170 component. The purpose of the present study was to continue the investigation of the race-of-face processing across multiple orientations. Event-related brain potentials (ERPs) and performance were recorded when Caucasian participants were required to categorize by race Caucasian and African faces presented in eight different angles of orientation. Three main observations were made: (1) the face-sensitive N170 is modulated by the race of faces, being larger in response to OR compared to SR faces; (2) face rotation affected this component in the same pattern for both racial groups; (3) the N170-ORE progressively disappeared as the faces moved away from their canonical orientation at the right hemisphere only. Thus, the current findings suggest that configural/holisitic information is extracted from faces of both racial groups, but that upright OR faces require increased demands.     

Lecturers' faces fatigue their students: Face identity aftereffects for dynamic and static faces

Face adaptation has been used as a tool to probe our representations for facial identity. It has also been claimed to play a functional role in face processing, perhaps calibrating the visual system towards encountered faces. However, for this to be so, face aftereffects must be observable following adaptation to ecologically valid moving stimuli, not just after prolonged viewing of static images. We adapted our participants to videos, static image sequences or single images of the faces of lecturers who were personally familiar to them. All three stimulus types produced significant, and equivalent, face identity aftereffects, demonstrating that aftereffects are not confined to static images but can occur after exposure to more naturalistic stimuli. It is also further evidence against explanations of face adaptation effects solely in terms of low-level visual processing.     

Early processing of emotional faces in children with autism: An event-related potential study

Social deficits are one of the most striking manifestations of autism spectrum disorders (ASDs). Among these social deficits, the recognition and understanding of emotional facial expressions has been widely reported to be affected in ASDs. We investigated emotional face processing in children with and without autism using event-related potentials (ERPs). High-functioning children with autism (n = 15, mean age = 10.5 ± 3.3 years) completed an implicit emotional task while visual ERPs were recorded. Two groups of typically developing children (chronological age-matched and verbal equivalent age-matched [both ns = 15, mean age = 7.7 ± 3.8 years]) also participated in this study. The early ERP responses to faces (P1 and N170) were delayed, and the P1 was smaller in children with autism than in typically developing children of the same chronological age, revealing that the first stages of emotional face processing are affected in autism. However, when matched by verbal equivalent age, only P1 amplitude remained affected in autism. Our results suggest that the emotional and facial processing difficulties in autism could start from atypicalities in visual perceptual processes involving rapid feedback to primary visual areas and subsequent holistic processing.     

男性对女性面孔吸引力的认知偏好: 来自ERP的证据

运用事件相关电位(ERPs)技术, 采用学习-再认实验任务, 探讨了男性对有、无吸引力女性面孔图片进行判断和再认时脑内时程的动态变化。行为数据结果表明, 男性对有吸引力女性面孔的反应时更长, 再认正确率更高。ERP结果发现, 有、无吸引力面孔诱发的ERP早成分和晚成分都存在显著差异, 最强效应出现在大脑皮层的中前部。在判断任务和再认任务中, 有吸引力的女性面孔都比无吸引力的女性面孔诱发出更大的ERP成分(分别为N300、P350~550ms和P160、N300~500ms、P500~700ms)。结果表明, 男性对有吸引力的女性面孔的判断和再认存在偏好。     

社交焦虑个体对正性面孔刺激的解释偏差

本研究分别在短时（60ms）和长时（无时间限制）条件下呈现匹配的正性和中性面孔,要求高、低社交焦虑被试选择更具威胁性的面孔,以验证两者对正性刺激是否存在主观解释偏差,并考察该偏差产生于认知加工的哪一阶段。结果发现,长时条件下,高焦虑组选择正性面孔的比例显著高于低焦虑组;短时条件下无显著差异。提示高社交焦虑个体对正性刺激存在主观、外显的解释偏差,他们更倾向于对正性刺激做出消极解释,并且这种偏差产生于认知加工的后期。