Vivid: How valence and arousal influence word processing under different task demands

In this study, we used event-related potentials to examine how different dimensions of emotion—valence and arousal—influence different stages of word processing under different task demands. In two experiments, two groups of participants viewed the same single emotional and neutral words while carrying out different tasks. In both experiments, valence (pleasant, unpleasant, and neutral) was fully crossed with arousal (high and low). We found that the task made a substantial contribution to how valence and arousal modulated the late positive complex (LPC), which is thought to reflect sustained evaluative processing (particularly of emotional stimuli). When participants performed a semantic categorization task in which emotion was not directly relevant to task performance, the LPC showed a larger amplitude for high-arousal than for low-arousal words, but no effect of valence. In contrast, when participants performed an overt valence categorization task, the LPC showed a large effect of valence (with unpleasant words eliciting the largest positivity), but no effect of arousal. These data show not only that valence and arousal act independently to influence word processing, but that their relative contributions to prolonged evaluative neural processes are strongly influenced by the situational demands (and by individual differences, as revealed in a subsequent analysis of subjective judgments).     

过犹不及：情绪的效价-唤醒度冲突在动机倾向上的分离

本研究通过两个实验考察不同效价度和唤醒度的情绪刺激是否存在动机倾向上的分离模式。实验1要求被试对表情图片的动机倾向（趋近/回避）进行主观评分,发现被试对低唤醒表情或积极表情有更加趋近的倾向。实验2以运动的线索启动动机倾向（趋近/回避）,完成情绪词效价判断任务,从内隐的角度考察情绪刺激是否存在动机倾向上的分离模式,结果发现,被试对动机倾向一致的情绪刺激的反应时更快。趋近的消极情绪词比趋近的积极情绪词的N2波幅更大,远离的低唤醒情绪词比趋近的低唤醒情绪词的LPC波幅更大。结果说明积极或者低唤醒的情绪刺激引发趋近倾向,而消极或高唤醒的情绪刺激引发回避倾向。     

Time flies when we read taboo words

Does time fly or stand still when one is reading highly arousing words? A temporal bisection task was used to test the effects of sexual taboo words on time perception. Forty participants judged the duration of sexual taboo, high-arousal negative, high-arousal positive, low-arousal negative, low-arousal positive, and category-related neutral words. The results support the hypothesis that sexual taboo stimuli receive more attention and reduce the perceived time that has passed (“time flies”)—the duration of high sexual taboo words was underestimated for taboo-word stimuli relative to all other word types. The findings are discussed in the context of internal clock theories of time perception.     

The effects of valence and arousal on the emotional modulation of time perception: evidence for multiple stages of processing

Previous research has demonstrated that both emotional valence and arousal can influence the subjective experience of time. The current research extends this work by (1) identifying how quickly this emotional modulation of time perception can occur and (2) examining whether valence and arousal have different effects at different stages of perception. These questions were addressed using a temporal bisection task. In each block of this task, participants are trained to distinguish between two different exposure durations. Participants are then shown stimuli presented at a number of durations that fall between the two learned times, and are asked to indicate whether the test stimulus was closer in duration to the shorter or longer learned item. In the current study, participants completed blocks of trials in which the durations were "Short" (100-300 ms) or "Long" (400-1600 ms). Stimuli consisted of neutral photographs as well as four categories of emotional images: high-arousal negative, high-arousal positive, low-arousal negative, and low-arousal positive. In Short blocks, arousing and nonarousing negative images were judged to have been shown for shorter durations than they actually were (i.e., the duration was underestimated); this effect occurred at durations as brief as 133 ms. In Long blocks, the display time for highly arousing negative items was overestimated, whereas durations were underestimated for highly arousing positive items and less arousing negative items. These data suggest that arousal and valence have different effects at different stages of perception, possibly due to the different neural structures involved at each stage of the emotional modulation of time perception.     

Valence evaluation with approaching or withdrawing cues: directly testing valence–arousal conflict theory

The valence–arousal conflict theory assumes that both valence and arousal will trigger approaching or withdrawing tendencies. It also predicts that the speed of processing emotional stimuli will depend on whether valence and arousal trigger conflicting or congruent motivational tendencies. However, most previous studies have provided evidence of the interaction between valence and arousal only, and have not provided direct proof of the interactive links between valence, arousal and motivational tendencies. The present study provides direct evidence for the relationship between approach–withdrawal tendencies and the valence–arousal conflict. In an empirical test, participants were instructed to judge the valence of emotional words after visual–spatial cues that appeared to be either approaching or withdrawing from participants. A three-way interaction (valence, arousal, and approach–withdrawal tendency) was observed such that the response time was shorter if participants responded to a negative high-arousal stimulus after a withdrawing cue, or to a positive low-arousal stimulus after an approaching cue. These findings suggest that the approach–withdrawal tendency indeed plays a crucial role in valence–arousal conflict, and that the effect depends on the congruency of valence, arousal and tendency at an early stage of processing.     

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 Effect of Positive Emotions with Different Arousal Levels on Thought–Action Repertoires1,2

This study examined whether the induction of different states of arousal via positive emotions broadens thought–action repertoires. Sixty-two Japanese undergraduate and graduate students were randomly assigned to (a) high-arousal positive emotion, (b) low-arousal positive emotion, and (c) neutral groups, after which they watched a 3-min film clip. Participants completed the Affect Grid to confirm their mood state before and after watching the film. Following this, they completed the Twenty Statements Test, which measures thought–action repertoires. A one-way analysis of variance was conducted on the Twenty Statements Test score. The results showed that high-arousal positive emotion broadened thought–action repertoires to a greater extent than did low-arousal positive emotion and the neutral state, while low-arousal positive emotion broadened such repertoires to a greater extent than did the neutral state. We discuss the different effects of high- and low-arousal positive emotions on thought–action repertoires.     

Emotions in word and face processing: Early and late cortical responses

Recent research suggests that emotion effects in word processing resemble those in other stimulus domains such as pictures or faces. The present study aims to provide more direct evidence for this notion by comparing emotion effects in word and face processing in a within-subject design. Event-related brain potentials (ERPs) were recorded as participants made decisions on the lexicality of emotionally positive, negative, and neutral German verbs or pseudowords, and on the integrity of intact happy, angry, and neutral faces or slightly distorted faces. Relative to neutral and negative stimuli both positive verbs and happy faces elicited posterior ERP negativities that were indistinguishable in scalp distribution and resembled the early posterior negativities reported by others. Importantly, these ERP modulations appeared at very different latencies. Therefore, it appears that similar brain systems reflect the decoding of both biological and symbolic emotional signals of positive valence, differing mainly in the speed of meaning access, which is more direct and faster for facial expressions than for words.     

Paying attention to emotional images with impact

Emotional stimuli receive high processing priority in attention and memory. This processing "advantage" is generally thought to be predominantly mediated by arousal. However, recent data suggest that ratings of an image's affective "impact" may be a better predictor of recollection than arousal or valence. One interpretation of these findings is that high-impact images may draw an individual's attention, thus facilitating subsequent processing. We investigated the allocation of visual attention to negative emotional images that differed in impact but were matched for valence, arousal, and other characteristics. Participants viewed a central image flanked by 2 neutral indoor or outdoor scenes and made speeded judgments about whether the neutral scenes matched. In Experiment 1, responses were slower on high-impact relative to low-impact or neutral trials. In Experiment 2, responses on high-arousal relative to low-arousal trials did not differ significantly. These data provide evidence for differential allocation of attention to distinct sets of negative, equally arousing images, and argue against the prevailing view that heightened attention to and processing of emotional stimuli relate simply to arousal or valence.     

Dissociation of event-related potentials indexing arousal and semantic cohesion during emotional word encoding

Event-related potential (ERP) studies have shown that emotional stimuli elicit greater amplitude late positive-polarity potentials (LPPs) than neutral stimuli. This effect has been attributed to arousal, but emotional stimuli are also more semantically coherent than uncategorized neutral stimuli. ERPs were recorded during encoding of positive, negative, uncategorized neutral, and categorized neutral words. Differences in LPP amplitude elicited by emotional versus uncategorized neutral stimuli were evident from 450 to 1000 ms. From 450 to 700 ms, LPP effects at midline and right hemisphere frontal electrodes indexed arousal, whereas LPP effects at left hemisphere centro-parietal electrodes indexed semantic cohesion. This dissociation helps specify the processes underlying emotional stimulus encoding, and suggests the need to control for semantic cohesion in emotional information processing studies.     

Affective recognition memory processing and event-related brain potentials

Recognition memory was examined for visual affective stimuli using behavioral and event-related brain potential (ERP) measures. Images from the International Affective Picture System (IAPS) that varied systematically in arousal level (low, high) and valence direction (unpleasant, pleasant) were first viewed passively. Then, during a response phase, the original images were intermixed with an equal number of new images and presented, and participants were instructed to press a button to indicate whether each stimulus picture was previously viewed (target) or new (foil). Participants were more sensitive to unpleasant- than to pleasant-valence stimuli and were biased to respond to high-arousal unpleasant stimuli as targets, whether the stimuli were previously viewed or new. Response times (RTs) to target stimuli were systematically affected by valence, whereas RTs to foil stimuli were influenced by arousal level. ERP component amplitudes were generally larger for high than for low arousal levels. The P300 (late positive component) amplitude was largest for high-arousal unpleasant target images. These and other amplitude effects suggest that high-arousal unpleasant stimuli engage a privileged memory-processing route during stimulus processing. Theoretical relationships between affective and memory processes are discussed.     

情绪词加工过程及其情绪效应特点：ERP的证据

语言是传递情绪信息的重要媒介, 探讨情绪语言的加工过程一直是情绪研究的重点。文章聚焦于情绪词加工的ERP研究, 介绍了情绪词加工中的ERP成分、效价与唤醒度的作用关系, 以及情绪词情绪效应的特点。情绪词加工的ERP成分包括非常早期的P1-N1成分, 早期的EPN成分和晚期的LPP成分; 效价和唤醒度均在情绪词加工中具有重要作用, 但两者的关系还未得到一致结论。相比情绪图片, 情绪词加工所引发的情绪效应更弱, 并且存在积极效价偏向。今后的研究还需进一步探讨影响情绪词情绪效应产生的相关因素; 进一步区分情绪标注词和情绪负载词, 探讨两类情绪词加工的异同。此外, 结合眼动追踪技术探讨自然语境中的情绪词加工机制也是未来研究的一个重要方向。     

Emotion's influence on memory for spatial and temporal context

Individuals report remembering emotional items vividly. It is debated whether this report reflects enhanced memory accuracy or a bias to believe emotional memories are vivid. We hypothesized emotion would enhance memory accuracy, improving memory for contextual details. The hallmark of episodic memory is that items are remembered in a spatial and temporal context, so we examined whether an item's valence (positive, negative) or arousal (high, low) would influence its ability to be remembered with those contextual details. Across two experiments, high-arousal items were remembered with spatial and temporal context more often than low-arousal items. Item valence did not influence memory for those details, although positive high-arousal items were recognized or recalled more often than negative items. These data suggest that emotion does not just bias participants to believe they have a vivid memory; rather, the arousal elicited by an event can benefit memory for some types of contextual details.     

Emotion's influence on memory for spatial and temporal context

Individuals report remembering emotional items vividly. It is debated whether this report reflects enhanced memory accuracy or a bias to believe emotional memories are vivid. We hypothesised emotion would enhance memory accuracy, improving memory for contextual details. The hallmark of episodic memory is that items are remembered in a spatial and temporal context, so we examined whether an item's valence (positive, negative) or arousal (high, low) would influence its ability to be remembered with those contextual details. Across two experiments, high-arousal items were remembered with spatial and temporal context more often than low-arousal items. Item valence did not influence memory for those details, although positive high-arousal items were recognised or recalled more often than negative items. These data suggest that emotion does not just bias participants to believe they have a vivid memory; rather, the arousal elicited by an event can benefit memory for some types of contextual details.     

Early effects of emotion on word immediate repetition priming: Electrophysiological and source localization evidence

The processing of a stimulus benefits from the previous exposure of an identical stimulus, which is known as immediate repetition priming (IRP). Although several experimental manipulations modulate the size of this effect, the influence of affective information is still unclear. In order to explore the temporo–spatial characteristics of the interaction between emotion and IRP, event-related potentials (ERPs) to negative and neutral target words were measured during a lexical decision task in an IRP paradigm. Temporal and spatial versions of principal components analyses were used to detect and quantify those ERP components associated with IRP. A source localization procedure provided information on the neural origin of these components. Behavioural analyses showed that reaction times to repeated negative and neutral words differed from those to unrepeated negative and neutral words, respectively. However, the interaction between repetition and emotion was only marginally significant. In contrast, ERP analyses revealed specific IRP effects for negative words: Repeated negative words elicited reduced P120/enhanced N170 effects and weaker activation suppression in the left inferior frontal gyrus than did unrepeated negative words. These results suggest that a word’s negative content captures attention interfering with IRP mechanisms, possibly at an early semantic stage of processing.     

Situation selection across adulthood: the role of arousal

In this study, we investigated age differences in situation selection to understand the role stimulus arousal plays in motivating age differences in this type of emotion regulation. Participants freely selected from a set of affective videos using information about the valence and arousal of each stimulus. There were age differences both in the valence and arousal of selected stimuli. Older adults selected more neutral and low-arousal stimuli while younger adults selected more negative and high-arousal stimuli. We consider these results in light of recent theoretical models and conclude that studies of age differences in emotion regulation must consider both valence and arousal.     

Electrophysiological differences in the processing of affective information in words and pictures

It is generally assumed that affective picture viewing is related to higher levels of physiological arousal than is the reading of emotional words. However, this assertion is based mainly on studies in which the processing of either words or pictures has been investigated under heterogenic conditions. Positive, negative, relaxing, neutral, and background (stimulus fragments) words and pictures were presented to subjects in two experiments under equivalent experimental conditions. In Experiment 1, neutral words elicited an enhanced late positive component (LPC) that was associated with an increased difficulty in discriminating neutral from background stimuli. In Experiment 2, high-arousing pictures elicited an enhanced early negativity and LPC that were related to a facilitated processing for these stimuli. Thus, it seems that under some circumstances, the processing of affective information captures attention only with more biologically relevant stimuli. Also, these data might be better interpreted on the basis of those models that postulate a different access to affective information for words and pictures.     

Remembering pictures: pleasure and arousal in memory.

Incidental memory performance for pictures that varied along the affective dimensions of pleasantness and arousal was assessed. For both an immediate and delayed (1 year later) free-recall task, only the arousal dimension had a stable effect on memory performance: Pictures rated as highly arousing were remembered better than low-arousal stimuli. This effect was corroborated in a speeded recognition test, in which high-arousal materials encoded earlier in the experiment produced faster reaction times than their low-arousal counterparts. Pleasantness affected reaction time decisions only for pictures not encoded earlier. These results suggest that whereas both the dimensions of pleasantness and arousal are processed at initial encoding, long-term memory performance is mainly affected by arousal.     

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.     

Positive and negative emotions modulate attention allocation in color-flanker task processing: Evidence from event related potentials

The purpose of this study was to explore the effects of emotions in conflict processing. Behavioral and event related potential (ERP) data were acquired from twenty participants while they were performing a color-flanker task, in which the stimuli were emotional and neutral words. Through temporal principal component analysis (PCA) of ERP, three PCA components were extracted with their time windows mapped to three ERP components: N1, N2 and P3. Further analysis revealed, when the stimuli were the positive words, N1 was marginally greater for the congruent condition than for the incongruent condition (p = .06); while the stimuli were the negative words, N1 was greater for the incongruent condition than for the congruent condition (p = .02); however, no significant interaction effect involving the valence of words (positive vs. negative) and the color congruency (congruent vs. incongruent) was found on N2, P3 and the behavior data. The result suggested that negative emotion might lead to more attention allocation in the incongruent processing, while positive emotion might lead to more attention allocation in the congruent processing. Furthermore, ERP source analysis in the present study confirmed anterior cingulate cortex was involved in the conflict monitoring mechanism.