Time course and task dependence of emotion effects in word processing

The emotional content of stimuli influences cognitive performance. In two experiments, we investigated the time course and mechanisms of emotional influences on visual word processing in various tasks by recording event-related brain potentials (ERPs). The stimuli were verbs of positive, negative, and neutral valence. In Experiment 1, where lexical decisions had to be performed on single verbs, both positive and negative verbs were processed more quickly than neutral verbs and elicited a distinct ERP component, starting around 370 msec. In Experiment 2, the verbs were embedded in a semantic context provided by single nouns. Likewise, structural, lexical, and semantic decisions for positive verbs were accelerated, and an ERP effect with a scalp distribution comparable to that in Experiment 1 now started about 200 msec earlier. These effects may signal an automatic allocation of attentional resources to emotionally arousing words, since they were not modulated by different task demands. In contrast, a later ERP effect of emotion was restricted to lexical and semantic decisions and, thus, appears to indicate more elaborated, task-dependent processing of emotional words.     

The influence of indirect and direct emotional processing on memory for facial expressions

We used the remember-know procedure (Tulving, 1985 ) to test the behavioural expression of memory following indirect and direct forms of emotional processing at encoding. Participants (N=32) viewed a series of facial expressions (happy, fearful, angry, and neutral) while performing tasks involving either indirect (gender discrimination) or direct (emotion discrimination) emotion processing. After a delay, participants completed a surprise recognition memory test. Our results revealed that indirect encoding of emotion produced enhanced memory for fearful faces whereas direct encoding of emotion produced enhanced memory for angry faces. In contrast, happy faces were better remembered than neutral faces after both indirect and direct encoding tasks. These findings suggest that fearful and angry faces benefit from a recollective advantage when they are encoded in a way that is consistent with the predictive nature of their threat. We propose that the broad memory advantage for happy faces may reflect a form of cognitive flexibility that is specific to positive emotions.     

Angry expressions strengthen the encoding and maintenance of face identity representations in visual working memory

Visual working memory (WM) for face identities is enhanced when faces express negative versus positive emotion. To determine the stage at which emotion exerts its influence on memory for person information, we isolated expression (angry/happy) to the encoding phase (Experiment 1; neutral test faces) or retrieval phase (Experiment 2; neutral study faces). WM was only enhanced by anger when expression was present at encoding, suggesting that retrieval mechanisms are not influenced by emotional expression. To examine whether emotional information is discarded on completion of encoding or sustained in WM, in Experiment 3 an emotional word categorisation task was inserted into the maintenance interval. Emotional congruence between word and face supported memory for angry but not for happy faces, suggesting that negative emotional information is preferentially sustained during WM maintenance. Our findings demonstrate that negative expressions exert sustained and beneficial effects on WM for faces that extend beyond encoding.     

注视方向和面部表情对注意朝向的影响

摘 要 本文以三种表情面孔为材料,运用事件相关电位（ERP）方法探讨表情线索在注意朝向中与注视转移发生的交互及两者如何共同影响观察者的反应。结果发现：（1）线索效应在三种表情面孔的两种SOA中都出现了;（2）SOA较长时,注视线索效应量间的显著差异出现在中性和恐惧面孔、高兴和恐惧面孔间;（3）面部表情的效应出现在了表情线索诱发的P1成分上;（4）目标诱发的P1和N1说明了注视线索效应的存在及与表情间的交互。结论：表情线索先对观察者的朝向反应产生影响,随后是注视线索及其与表情线索发生的交互。     

Interplay of emotional valence and concreteness in word processing: An event-related potential study with verbs

The functional locus of emotional valence in word processing remains an open question. In event-related potentials, emotion has been found to elicit an early posterior negativity (EPN), which is assumed to reflect attention catching by the words’ meaning. Previously, the EPN was modulated by word category with verbs exhibiting longer EPN latencies compared with other word categories. Here we examined whether concreteness, a semantic variable, influences emotion processing. Within a lexical decision task for verbs, emotional valence (positive, negative, and neutral) was orthogonally combined with concreteness (concrete and abstract). EPN onset was found already at 250 ms post-stimulus for concrete verbs, whereas it started 50 ms later for abstract verbs. Concreteness effects occurred after the start of main effects of emotion. Thus, the elicitation of the EPN seems to be based on semantic processes, with emotional valence being accessed before other semantic aspects such as concreteness of verbs.     

Proactive and reactive control depends on emotional valence: a Stroop study with emotional expressions and words

We examined proactive and reactive control effects in the context of task-relevant happy, sad, and angry facial expressions on a face-word Stroop task. Participants identified the emotion expressed by a face that contained a congruent or incongruent emotional word (happy/sad/angry). Proactive control effects were measured in terms of the reduction in Stroop interference (difference between incongruent and congruent trials) as a function of previous trial emotion and previous trial congruence. Reactive control effects were measured in terms of the reduction in Stroop interference as a function of current trial emotion and previous trial congruence. Previous trial negative emotions exert greater influence on proactive control than the positive emotion. Sad faces in the previous trial resulted in greater reduction in the Stroop interference for happy faces in the current trial. However, current trial angry faces showed stronger adaptation effects compared to happy faces. Thus, both proactive and reactive control mechanisms are dependent on emotional valence of task-relevant stimuli.     

Mapping the time course of the positive classification advantage: An ERP study

The aim of the present study was to investigate the time course of the positive advantage in the expression classification of faces by recording event-related potentials (ERPs). Although neutral faces were classified more quickly than either happy or sad faces, a significant positive classification advantage (PCA)—that is, faster classification for happy than for sad faces—was found. For ERP data, as compared with sad faces, happy faces elicited a smaller N170 and a larger posterior N2 component. The P3 was modulated by facial expressions with higher amplitudes and shorter latencies for both happy and neutral stimuli than for sad stimuli, and the reaction times were significantly correlated with the amplitude and latency of the P3. Overall, these data showed robust PCA in expression classification, starting when the stimulus has been recognized as a face revealed by the N170 component.     

Differential emotion attribution to neutral faces of own and other races

Past research has demonstrated differential recognition of emotion on faces of different races. This paper reports the first study to explore differential emotion attribution to neutral faces of different races. Chinese and Caucasian adults viewed a series of Chinese and Caucasian neutral faces and judged their outward facial expression: neutral, positive, or negative. The results showed that both Chinese and Caucasian viewers perceived more Chinese faces than Caucasian faces as neutral. Nevertheless, Chinese viewers attributed positive emotion to Caucasian faces more than to Chinese faces, whereas Caucasian viewers attributed negative emotion to Caucasian faces more than to Chinese faces. Moreover, Chinese viewers attributed negative and neutral emotion to the faces of both races without significant difference in frequency, whereas Caucasian viewers mostly attributed neutral emotion to the faces. These differences between Chinese and Caucasian viewers may be due to differential visual experience, culture, racial stereotype, or expectation of the experiment. We also used eye tracking among the Chinese participants to explore the relationship between face-processing strategy and emotion attribution to neutral faces. The results showed that the interaction between emotion attribution and face race was significant on face-processing strategy, such as fixation proportion on eyes and saccade amplitude. Additionally, pupil size during processing Caucasian faces was larger than during processing Chinese faces.     

When does the brain distinguish between genuine and ambiguous smiles? An ERP study

Event-related brain potentials (ERPs) were recorded to assess the processing time course of ambiguous facial expressions with a smiling mouth but neutral, fearful, or angry eyes, in comparison with genuinely happy faces (a smile and happy eyes) and non-happy faces (neutral, fearful, or angry mouth and eyes). Participants judged whether the faces looked truly happy or not. Electroencephalographic recordings were made from 64 scalp electrodes to generate ERPs. The neural activation patterns showed early P200 sensitivity (differences between negative and positive or neutral expressions) and EPN sensitivity (differences between positive and neutral expressions) to emotional valence. In contrast, sensitivity to ambiguity (differences between genuine and ambiguous expressions) emerged only in later LPP components. Discrimination of emotional vs. neutral affect occurs between 180 and 430 ms from stimulus onset, whereas the detection and resolution of ambiguity takes place between 470 and 720 ms. In addition, while blended expressions involving a smile with angry eyes can be identified as not happy in the P200 (175–240 ms) component, smiles with fearful or neutral eyes produce the same ERP pattern as genuinely happy faces, thus revealing poor discrimination.     

The relationship of positive and negative expressiveness to the processing of emotion information

The tendency to express emotions non-verbally is positively related to perception of emotions in oneself. This study examined its relationship to perception of emotions in others. In 40 healthy adults, EEG theta synchronization was used to indicate emotion processing following presentation of happy, angry, and neutral faces. Both positive and negative expressiveness were associated with higher emotional sensitivity, as shown by cortical responses to facial expressions during the early, unconscious processing stage. At the late, conscious processing stage, positive expressiveness was associated with higher sensitivity to happy faces but lower sensitivity to angry faces. Thus, positive expressiveness predisposes people to allocate fewer attentional resources for conscious perception of angry faces. In contrast, negative expressiveness was consistently associated with higher sensitivity. The effects of positive expressiveness occurred in cortical areas that deal with emotions, but the effects of negative expressiveness occurred in areas engaged in self-referential processes in the context of social relationships.     

情绪效价及强度对词汇加工的影响

以46名大学生为被试,以不同词性（名词&动词）的汉语双字正性情绪词、负性情绪词、中性词作为刺激材料,考察情绪效价强度（极端、中等、中性）对词性判断加工的影响。结果表明：（1）动词的词性判断比名词难,且该难度会受到高强度情绪信息的影响而扩大。（2）情绪效价及强度对名词加工的影响表现在两个方面：极端正性情绪易化对名词的加工,增强名词加工的优势效应;而中等和极端负性情绪干扰对名词的词性判断,削弱名词加工的优势效应。（3）除了受到性别、性格等因素的影响外,情绪效价强度效应的具体表现还受刺激类型的调制。     

The role of spatial attention in the processing of facial expression: An ERP study of rapid brain responses to six basic emotions

To investigate the time course of emotional expression processing, we recorded ERP responses to stimulus arrays containing neutral versus angry, disgusted, fearful, happy, sad, or surprised faces. In one half of the experiment, the task was to discriminate emotional and neutral facial expressions. Here, an enhanced early frontocentral positivity was elicited in response to emotional as opposed to neutral faces, followed by a broadly distributed positivity and an enhanced negativity at lateral posterior sites. These emotional expression effects were very similar for all six basic emotional expressions. In the other half of the experiment, attention was directed away from the faces toward a demanding perceptual discrimination task. Under these conditions, emotional expression effects were completely eliminated, demonstrating that brain processes involved in the detection and analysis of facial expression require focal attention. The face-specific N170 component was unaffected by any emotional expression, supporting the hypothesis that structural encoding and expression analysis are independent processes.     

Emotional context at learning systematically biases memory for facial information

Emotion influences memory in many ways. For example, when a mood-dependent processing shift is operative, happy moods promote global processing and sad moods direct attention to local features of complex visual stimuli. We hypothesized that an emotional context associated with to-be-learned facial stimuli could preferentially promote global or local processing. At learning, faces with neutral expressions were paired with a narrative providing either a happy or a sad context. At test, faces were presented in an upright or inverted orientation, emphasizing configural or analytical processing, respectively. A recognition advantage was found for upright faces learned in happy contexts relative to those in sad contexts, whereas recognition was better for inverted faces learned in sad contexts than for those in happy contexts. We thus infer that a positive emotional context prompted more effective storage of holistic, configural, or global facial information, whereas a negative emotional context prompted relatively more effective storage of local or feature-based facial information     

An electrophysiological investigation into the automaticity of emotional face processing in high versus low trait anxious individuals

To examine the extent of automaticity of emotional face processing in high versus low trait anxious participants, event-related potentials (ERPs) were recorded to emotional (fearful, happy) and neutral faces under varying task demands (low load, high load). Results showed that perceptual encoding of emotional faces, as reflected in P1 and early posterior negativity components, was unaffected by the availability of processing resources. In contrast, the postperceptual registration and storage of emotion-related information, as reflected in the late positive potential component at frontal locations, was influenced by the availability of processing resources, and this effect was further modulated by level of trait anxiety. Specifically, frontal ERP augmentations to emotional faces were eliminated in the more demanding task for low trait anxious participants, whereas ERP enhancements to emotional faces were unaffected by task load in high trait anxious participants. This result suggests greater automaticity in processing affective information in high trait anxious participants.     

The effect of congenital deafness on cerebral asymmetry in the perception of emotional and non-emotional faces.

Functional hemispheric specialization in recognizing faces expressing emotions was investigated in 18 normal hearing and 18 congenitally deaf children aged 13-14 years. Three kinds of faces were presented: happy, to express positive emotions, sad, to express negative emotions, and neutral. The subjects' task was to recognize the test face exposed for 20 msec in the left or right visual field. The subjects answered by pointing at the exposed stimulus on the response card that contained three different faces. The errors committed in expositions of faces in the left and right visual field were analyzed. In the control group the right hemisphere dominated in case of sad and neutral faces. There were no significant differences in recognition of happy faces. The differentiated hemispheric organization pattern in normal hearing persons supports the hypothesis of different processing of positive and negative emotions expressed by faces. The observed hemispheric asymmetry was a result of two factors: (1) processing of faces as complex patterns requiring visuo-spatial analysis, and (2) processing of emotions contained in them. Functional hemispheric asymmetry was not observed in the group of deaf children for any kind of emotion expressed in the presented faces. The results suggest that lack of auditory experience influences the organization of functional hemispheric specialization. It can be supposed that in deaf children, the analysis of information contained in emotional faces takes place in both hemispheres.     

两种任务下情绪韵律的加工进程

采用ERP技术分别考察了情绪判断和性别判断任务下情绪韵律的加工进程。结果显示：在175-275ms时间段,情绪韵律的加工受实验任务的调节,情绪判断任务下存在效价主效应及负性偏向,愤怒比高兴和中性诱发了更正的P2成分,而性别判断任务则无效价效应。在后期评价加工及反应准备阶段（400-800ms）,两种任务下,愤怒都比高兴和中性诱发了更正的晚成分。上述结果说明,不同情绪韵律的识别存在不同的认知机制,并在一定程度上会受加工任务的调节。     

Fearful expressions enhance recognition memory: electrophysiological evidence

Facial expressions play a key role in affective and social behavior. However, the temporal dynamics of the brain responses to emotional faces remain still unclear, in particular an open question is at what stage of face processing expressions might influence encoding and recognition memory. To try and answer this question we recorded the event-related potentials (ERPs) elicited in an old/new recognition task. A novel aspect of the present design was that whereas faces were presented during the study phase with either a happy, fearful or neutral expression, they were always neutral during the memory retrieval task. The ERP results showed three main findings: An enhanced early fronto-central positivity for faces encoded as fearful, both during the study and the retrieval phase. During encoding subsequent memory (Dm effect) was influenced by emotion. At retrieval the early components P100 and N170 were modulated by the emotional expression of the face at the encoding phase. Finally, the later ERP components related to recognition memory were modulated by the previously encoded facial expressions. Overall, these results suggest that face recognition is modulated by top-down influences from brain areas associated with emotional memory, enhancing encoding and retrieval in particular for fearful emotional expressions.     

Emotional faces in neutral crowds: Detecting displays of anger,happiness, and sadness on schematic and photographic images of faces

Detection of angry, happy and sad faces among neutral backgrounds was investigated in three single emotion tasks and an emotion comparison task using schematic (Experiment 1) and photographic faces (Experiment 2). Both experiments provided evidence for the preferential detection of anger displays over displays of other negative or positive emotions in tasks that employed all three target emotions. Evidence for preferential detection of negative emotion in general was found only with schematic faces. The present results are consistent with the notion that the detection of displays of anger, and to some extent sadness, does not reflect on a pre-attentive mechanism, but is the result of a more efficient visual search than is the detection of positive emotion.     

An emotional Stroop task with faces and words. A comparison of young and older adults

AntecedentsGiven the contradictions of previous studies on the changes in attentional responses produced in aging a Stroop emotional task was proposed to compare young and older adults to words or faces with an emotional valence.MethodThe words happy or sad were superimposed on faces that express the emotion of happiness or sadness. The emotion expressed by the word and the face could agree or not (cued and uncued trials, respectively). 85 young and 66 healthy older adults had to identify both faces and words separately, and the interference between the two types of stimuli was examined.ResultsAn interference effect was observed for both types of stimuli in both groups. There was more interference on positive faces and words than on negative stimuli.ConclusionsOlder adults had more difficulty than younger in focusing on positive uncued trials, whereas there was no difference across samples on negative uncued trials.     

Emotion words affect eye fixations during reading

Emotion words are generally characterized as possessing high arousal and extreme valence and have typically been investigated in paradigms in which they are presented and measured as single words. This study examined whether a word's emotional qualities influenced the time spent viewing that word in the context of normal reading. Eye movements were monitored as participants read sentences containing an emotionally positive (e.g., lucky), negative (e.g., angry), or neutral (e.g., plain) word. Target word frequency (high or low) was additionally varied to help determine the temporal locus of emotion effects, with interactive results suggesting an early lexical locus of emotion processing. In general, measures of target fixation time demonstrated significant effects of emotion and frequency as well as an interaction. The interaction arose from differential effects with negative words that were dependent on word frequency. Fixation times on emotion words (positive or negative) were consistently faster than those on neutral words with one exception-high-frequency negative words were read no faster than their neutral counterparts. These effects emerged in the earliest eye movement measures, namely, first and single fixation duration, suggesting that emotionality, as defined by arousal and valence, modulates lexical processing. Possible mechanisms involved in processing emotion words are discussed, including automatic vigilance and desensitization, both of which imply a key role for word frequency. Finally, it is important that early lexical effects of emotion processing can be established within the ecologically valid context of fluent reading.