Event-related potentials of emotional memory: encoding pleasant,unpleasant, and neutral pictures

Emotional events tend to be remembered better than nonemotional events. We investigated this phenomenon by measuring two event-related potential (ERP) effects: the emotion effect (more positive ERPs for pleasant or unpleasant stimuli than for neutral stimuli) and the subsequent memory effect (more positive ERPs for subsequently remembered items than for subsequently forgotten items). ERPs were measured while subjects rated the emotional content of pleasant, unpleasant, and neutral pictures. As was expected, subsequent recall was better for pleasant and unpleasant pictures than for neutral pictures. The emotion effect was sensitive to arousal in parietal electrodes and to both arousal and valence in frontocentral electrodes. The subsequent memory effect at centroparietal electrodes was greater for emotional pictures than for neutral pictures during an early epoch (400-600 msec). This result suggests that emotional information has privileged access to processing resources, possibly leading to better memory formation.     

A misleading feeling of happiness: metamemory for positive emotional and neutral pictures

Emotional information is often remembered better than neutral information, but the emotional benefit for positive information is less consistently observed than the benefit for negative information. The current study examined whether positive emotional pictures are recognised better than neutral pictures, and further examined whether participants can predict how emotion affects picture recognition. In two experiments, participants studied a mixed list of positive and neutral pictures, and made immediate judgements of learning (JOLs). JOLs for positive pictures were consistently higher than for neutral pictures. However, recognition performance displayed an inconsistent pattern. In Experiment 1, neutral pictures were more discriminable than positive pictures, but Experiment 2 found no difference in recognition based on emotional content. Despite participants’ beliefs, positive emotional content does not appear to consistently benefit picture memory.     

Effect of negative emotional pictures on associative memory for peripheral information

We investigated the influence of negative emotional pictures on associative memory. A visual object was embedded in the periphery of negative emotional or neutral pictures. Memory was assessed for central item (pictorial) information, peripheral (object) information, and the association between item and peripheral information. On tests of item information, negative emotional pictures were remembered better than neutral pictures. However, associative memory between item and peripheral information was less accurate when the pictures were negative compared to neutral. This occurred despite equivalent recall (Experiments 1 and 2) and recognition (Experiment 2) for the peripheral objects themselves. Further experiments confirmed that performance on the associative test was not influenced by testing order (Experiment 3). These findings suggest that negative emotional arousal can particularly disrupt the associative binding of peripheral information to a central emotional event.     

Goal-relevant situations facilitate memory of neutral faces

Emotional situations are typically better remembered than neutral situations, but the psychological conditions and brain mechanisms underlying this effect remain debated. Stimulus valence and affective arousal have been suggested to explain the major role of emotional stimuli in memory facilitation. However, neither valence nor arousal are sufficient affective dimensions to explain the effect of memory facilitation. Several studies showed that negative and positive details are better remembered than neutral details. However, other studies showed that neutral information encoded and coupled with arousal did not result in a memory advantage compared with neutral information not coupled with arousal. Therefore, we suggest that the fundamental affective dimension responsible for memory facilitation is goal relevance. To test this hypothesis at behavioral and neural levels, we conducted a functional magnetic resonance imaging study and used neutral faces embedded in goal-relevant or goal-irrelevant daily life situations. At the behavioral level, we found that neutral faces encountered in goal-relevant situations were better remembered than those encountered in goal-irrelevant situations. To explain this effect, we studied neural activations involved in goal-relevant processing at encoding and in subsequent neutral face recognition. At encoding, activation of emotional brain regions (anterior cingulate, ventral striatum, ventral tegmental area, and substantia nigra) was greater for processing of goal-relevant situations than for processing of goal-irrelevant situations. At the recognition phase, despite the presentation of neutral faces, brain activation involved in social processing (superior temporal sulcus) to successfully remember identities was greater for previously encountered faces in goal-relevant than in goal-irrelevant situations.     

Effects of level of processing on memory for affectively valenced words

In this study we tested whether subjects remember affectively valenced stimuli better than neutral stimuli when their attention is not focused on the affective charge of the stimuli during encoding. We tested memory for positive, negative, and neutral words in three memory tasks and using two encoding conditions (physical and semantic). Our results show that subjects remember affectively valenced stimuli better than neutral stimuli when they encode them according to their emotional content as well as to other features of the stimuli. However, although both positive and negative words are better remembered than neutral ones when semantically encoded, only positive words are better remembered than neutral ones when physically encoded. These results suggest that the affective charge of a stimulus (especially when positive) can affect retention even when a subject's attention has not focused on it during encoding.     

Memory enhancement for emotional words: Are emotional words more vividly remembered than neutral words?

Individuals are more likely to remember negative information than neutral information. In the experiments reported here, we examined whether individuals were also more likely to remember details of the presentation of negative words, as compared with neutral words. In Experiment 1, the remember-know procedure was used to examine the effect of emotion on the vividness of an individual's memory, showing that remember responses were more frequently assigned to negative words than neutral words. In Experiment 2, a source memory paradigm was used, and again, evidence that individuals' memories were more detailed for negative than for neutral words was found. In Experiments 3-6, we examined the relative contribution of valence and arousal, finding that both dimensions increased the vividness of remembered information (i.e., items with valence only and those that elicited arousal were better remembered than neutral information) but that the effect was greater for words that evoked arousal than for those with valence only. The results support a qualitative, as well as a quantitative, memory benefit for emotional, as compared with neutral, words.     

焦虑情绪对图像信息意识提取和无意识提取影响的实验研究

采用加工分离程序,以不同性价图片为实验材料,考察了特质焦虑、启动焦虑和非焦虑三种焦虑类型对图片信息意识提取和无意识提取的影响,结果表明：（1）不同焦虑类型对图像信息的意识提取和无意识提取均有影响,其中特质焦虑对图像的无意识提取更敏感,非焦虑状态对意识提取更敏感;（2）特质焦虑明显促进了负性图片的意识和无意识提取且干扰了正性图片的提取,启动焦虑促进了对负性图片的意识提取。     

双加工再认提取中的情绪记忆增强效应

根据双加工理论, 再认提取可以划分为两种不同的加工：熟悉性与回想。以往的研究普遍认为情绪对再认提取具有增强效应, 但是情绪对再认记忆中两种不同加工方式(熟悉性与回想)的增强效应的神经机制尚存争议。本研究以ERP作为测量手段, 采用修正的“记得/知道”范式对情绪图片进行再认测验, 旨在探究在学习?测验间隔较长的条件下, 情绪信息如何对熟悉性与回想产生增强效应。在行为结果中, 对于知道判断, 情绪图片的记忆表现显著高于中性图片, 情绪效价间没有差异; 对于记得判断, 负性情绪图片的记忆表现要显著高于正性与中性图片。在ERP数据上, 对于知道判断, 情绪图片的FN400新旧效应有增强作用。对于记得判断, 负性图片的LPC的新旧效应波幅显著高于中性与负性图片; 而正性图片的LPC新旧效应增强作用不显著。以上证据表明：学习?测验间隔较长的情况下, 熟悉性再认提取中, 情绪记忆增强效应主要体现在情绪唤醒对记忆强度的提高, 而不仅仅体现在情绪效价对熟悉判断反应倾向的影响。在回想的再认提取中, 情绪效价的调节占据主导地位, 负性情绪图片有显著的情绪记忆增强效应; 正性情绪图片则不具有增强效应。     

Are the memories of older adults positively biased?

There is disagreement in the literature about whether a "positivity effect" in memory performance exists in older adults. To assess the generalizability of the effect, the authors examined memory for autobiographical, picture, and word information in a group of younger (17-29 years old) and older (60-84 years old) adults. For the autobiographical memory task, the authors asked participants to produce 4 positive, 4 negative, and 4 neutral recent autobiographical memories and to recall these a week later. For the picture and word tasks, participants studied photos or words of different valences (positive, negative, neutral) and later remembered them on a free-recall test. The authors found significant correlations in memory performance, across task material, for recall of both positive and neutral valence autobiographical events, pictures, and words. When the authors examined accurate memories, they failed to find consistent evidence, across the different types of material, of a positivity effect in either age group. However, the false memory findings offer more consistent support for a positivity effect in older adults. During recall of all 3 types of material, older participants recalled more false positive than false negative memories.     

Effects of level of processing on emotional memory: gist and details

The object of this study was to investigate whether level of processing (LOP) modulates enhanced memory performance for emotional stimuli, and, if so, whether the LOP effects relate to their gist and details. During the study phase, participants were presented with colourful pictures with negative, neutral and positive valences and encoded the emotional pictures under either a semantic (living/non-living judgement) or a perceptual (left/right position judgement) condition. During the test phase, they judged whether the presented picture was old or new in Experiments 1 and 2, and also judged whether a specific concept, labelled using words, had been studied in Experiment 2. The results showed that under both encoding conditions, the details of both negative and positive pictures were recognised better than those of neutral pictures. Also, the gist of negative pictures was recognised better than that of neutral pictures but only under the semantic condition. These data provide evidence that the LOP differentially modulates enhanced emotional memory for gist and details of pictures.     

不同延时条件下的情绪记忆鲜活性

大量研究表明,情绪在一定程度上提高了记忆的准确性,但是情绪对记忆鲜活性的影响更大,该文关注延时条件下情绪记忆鲜活性的研究。研究采用记得/知道范式,操控图片情绪性和测验延时变量,结果发现情绪记忆的记得成绩好于中性记忆,且在不同延时测验下,正性高唤醒图片的记得成绩下降由慢到快再到慢的变化,负性高唤醒图片的记得下降由快到慢变化,而中性则快速下降。说明情绪记忆更具鲜活性,且是效价在高唤醒下起的作用。     

Lateral and medial prefrontal contributions to emotion generation by semantic elaboration during episodic encoding

Memories for emotion-laden stimuli are remembered more accurately than those for neutral stimuli. Although this enhancement reflects stimulus-driven modulation of memory by emotions, functional neuroimaging evidence of the interacting mechanisms between emotions generated by intentional processes, such as semantic elaboration, and memory is scarce. The present fMRI study investigated how encoding-related activation is modulated by emotions generated during the process of semantic elaboration. During encoding with fMRI, healthy young adults viewed neutral (target) pictures either passively or with semantic elaboration. In semantic elaboration, participants imagined background stories related to the pictures. Encoding trials with semantic elaboration were subdivided into conditions in which participants imagined negative, positive, or neutral stories. One week later, memories for target pictures were tested. In behavioral results, memories for target pictures were significantly enhanced by semantic elaboration, compared to passive viewing, and the memory enhancement was more remarkable when negative or positive stories were imagined. fMRI results demonstrated that activations in the left inferior frontal gyrus and dorsal medial prefrontal cortex (dmPFC) were greater during the encoding of target pictures with semantic elaboration than those with passive viewing, and that these activations further increased during encoding with semantic elaboration of emotional stories than of neutral stories. Functional connectivity between the left inferior frontal gyrus and dmPFC/hippocampus during encoding significantly predicted retrieval accuracies of memories encoded with self-generated emotional stories. These findings suggest that networks including the left inferior frontal region, dmPFC, and hippocampus could contribute to the modulation of memories encoded with the emotion generation.     

Effect of negative emotional content on working memory and long-term memory

In long-term memory, negative information is better remembered than neutral information. Differences in processes important to working memory may contribute to this emotional memory enhancement. To examine the effect that the emotional content of stimuli has on working memory performance, the authors asked participants to perform working memory tasks with negative and neutral stimuli. Task accuracy was unaffected by the emotional content of the stimuli. Reaction times also did not differ for negative relative to neutral words, but on an n-back task using faces, participants were slower to respond to fearful faces than to neutral faces. These results suggest that although emotional content does not have a robust effect on working memory, in some instances emotional salience can impede working memory performance.     

Orienting, emotion, and memory: phasic and tonic variation in heart rate predicts memory for emotional pictures in men

Arousal-related processes associated with heightened heart rate (HR) predict memory enhancement, especially for emotionally arousing stimuli. In addition, phasic HR deceleration reflects "orienting" and sensory receptivity during perception of stimuli. We hypothesized that both tonic elevations in HR as well as phasic HR deceleration during viewing of pictures would be associated with deeper encoding and better subsequent memory for stimuli. Emotional pictures are more memorable and cause greater HR deceleration than neutral pictures. Thus, we predicted that the relations between cardiac activity and memory enhancement would be most pronounced for emotionally-laden compared to neutral pictures. We measured HR in 53 males during viewing of unpleasant, neutral, and pleasant pictures, and tested memory for the pictures two days later. Phasic HR deceleration during viewing of individual pictures was greater for subsequently remembered than forgotten pictures across all three emotion categories. Elevated mean HR across the entire encoding epoch also predicted better memory performance, but only for emotionally arousing pictures. Elevated mean HR and phasic HR deceleration were associated, such that individuals with greater tonic HR also showed greater HR decelerations during picture viewing, but only for emotionally arousing pictures. Results suggest that tonic elevations in HR are associated both with greater orienting and heightened memory for emotionally arousing stimuli.     

Reality monitoring and memory distortion: Effects of negative, arousing content

Although individuals often claim to vividly remember negatively arousing information, few studies have been performed to examine whether this emotional information is remembered more accurately than nonemotional information. In the present study, we investigated whether the emotional content of items modulates the accuracy with which individuals make reality-monitoring decisions. Participants (young adults, 18-35 years of age) distinguished imagined from seen words (Experiments 1 and 3A) or objects (Experiments 2 and 3B). Half of the items studied in each condition (presented and imagined) were negative and arousing, and half were neutral. The participants mistook imagined items for presented ones, but the number of reality-monitoring errors was lower for the arousing items than for the neutral items. Negative, arousing items appear to be remembered with contextual detail more frequently than are neutral items, leading memory for this emotional information to be less prone to distortion than is memory for neutral information. Thus, negative arousal can enhance not only the subjective vividness of a memory, but also a memory's accuracy.     

Memory for emotional words: The role of semantic relatedness,encoding task and affective valence

Emotional stimuli have been repeatedly demonstrated to be better remembered than neutral ones. The aim of the present study was to test whether this advantage in memory is mainly produced by the affective content of the stimuli or it can be rather accounted for by factors such as semantic relatedness or type of encoding task. The valence of the stimuli (positive, negative and neutral words that could be either semantically related or unrelated) as well as the type of encoding task (focused on either familiarity or emotionality) was manipulated. The results revealed an advantage in memory for emotional words (either positive or negative) regardless of semantic relatedness. Importantly, this advantage was modulated by the encoding task, as it was reliable only in the task which focused on emotionality. These findings suggest that congruity with the dimension attended at encoding might contribute to the superiority in memory for emotional words, thus offering us a more complex picture of the underlying mechanisms behind the advantage for emotional information in memory.     

The role of age on reactivity and memory for emotional pictures

The purpose of this study was to investigate subjects' reactivity to emotional pictures and their recollection of these pictures, and to examine these two factors as they relate to age. Adolescents and young adults were shown emotionally arousing scenic pictures for long (4-s) and very brief (50-ms) durations. Recognition of the pictures and recall and recognition of words presented along with the pictures were assessed both immediately after the presentation and six weeks later. The results showed that very negative pictures are retained better than neutral or even positive pictures, and that very negative pictures reduce memory for associated information. It was also found that adolescents show a somewhat lower reactivity to very negative pictures and a higher degree of retention of these pictures than adults. The results are discussed in relation to (a) habituation effects, (b) strategies that subjects might develop to block emotional involvement, and (c) the notion that watching violence might serve as a powerful prime to socially undesirable behaviour.     

Culture impacts the magnitude of the emotion-induced memory trade-off effect

The present study assessed the extent to which culture impacts the emotion-induced memory trade-off effect. This trade-off effect occurs because emotional items are better remembered than neutral ones, but this advantage comes at the expense of memory for backgrounds such that neutral backgrounds are remembered worse when they occurred with an emotional item than with a neutral one. Cultures differ in their prioritisation of focal object versus contextual background information, with Westerners focusing more on objects and Easterners focusing more on backgrounds. Americans, a Western culture, and Turks, an Eastern-influenced culture, incidentally encoded positive, negative, and neutral items placed against neutral backgrounds, and then completed a surprise memory test with the items and backgrounds tested separately. Results revealed a reduced trade-off for Turks compared to Americans. Although both groups exhibited an emotional enhancement in item memory, Turks did not show a decrement in memory for backgrounds that had been paired with emotional items. These findings complement prior ones showing reductions in trade-off effects as a result of task instructions. Here, we suggest that a contextual-focus at the level of culture can mitigate trade-off effects in emotional memory.     

Memory for Emotional Content from Entertainment Film: The Role of Subtitles,Sex, and Empathy

A major component of consuming filmed entertainment is vicariously experiencing emotions of the filmed characters, yet little is known about how this occurs. Four experiments assessed memory for emotions felt by characters in extended film clips from either a contemporary farce (Overboard) or a historical drama (Sense and Sensibility) under various conditions of native or foreign language in the dialogue or subtitles. English-speaking participants watched a clip and then assessed on 6-point scales specific positive and negative affect felt by characters at various points during the film. Both positive and negative affect felt by characters in both films were perceived and remembered better in conditions with English sound or subtitles than in conditions with no English channel, although, unexpectedly, spoken dialogue or subtitles alone were equally effective at conveying emotion. Overall, emotion memory from the contemporary farce was better than from the historical drama and was surprisingly good even in conditions with no English, especially for the farce. Conditions with only sound, subtitles, or pictures were very comparable to each other. Participants higher in trait fantasy empathy remembered emotions better. The components of an eventual model of emotional comprehension were sketched.     

记忆编码中目标与背景的情绪一致性对记忆提取的影响

摘 要 本研究将经典情绪启动范式和学习-再认范式相结合,探讨学习时启动与目标的情绪一致性对目标再认的影响。在记忆编码阶段,以情绪面孔图片为启动刺激、一般情绪图片为目标刺激,要求被试对目标图片的效价进行判断;在提取阶段向被试呈现一般情绪图片,要求被试判断是否在前一阶段见过。结果表明,编码阶段的加工背景对记忆提取产生了显著影响。一致启动促进了认知加工与记忆编码,提高了再认正确率。ERP结果也表明,在目标刺激呈现后300-500ms,编码时的情绪一致性对再认阶段消极目标诱发的ERP产生了显著影响。