Time-limited effects of emotional arousal on item and source memory

Two experiments investigated the time-limited effects of emotional arousal on consolidation of item and source memory. In Experiment 1, participants memorized words (items) and the corresponding speakers (sources) and then took an immediate free recall test. Then they watched a neutral, positive, or negative video 5, 35, or 50?min after learning, and 24 hours later they took surprise memory tests. Experiment 2 was similar to Experiment 1 except that (a) a reality monitoring task was used; (b) elicitation delays of 5, 30, and 45?min were used; and (c) delayed memory tests were given 60?min after learning. Both experiments showed that, regardless of elicitation delay, emotional arousal did not enhance item recall memory. Second, both experiments showed that negative arousal enhanced delayed item recognition memory only at the medium elicitation delay, but not in the shorter or longer delays. Positive arousal enhanced performance only in Experiment 1. Third, regardless of elicitation delay, emotional arousal had little effect on source memory. These findings have implications for theories of emotion and memory, suggesting that emotion effects are contingent upon the nature of the memory task and elicitation delay.     

Effect of post-encoding emotion on recollection and familiarity for pictures

Although prior studies have examined the effect of post-encoding emotional arousal on recognition memory for words, it is unknown whether the enhancement effect observed on words generalizes to pictures. Furthermore, prior studies using words have showed that the effect of emotional arousal can be modulated by stimuli valence and delay in emotion induction, but it is unclear whether such modulation can extend to pictures and whether other factors such as encoding method (incidental vs. intentional encoding) can be modulatory. Five experiments were conducted to answer these questions. In Experiment 1, participants encoded a list of neutral and negative pictures and then watched a 3-min neutral or negative video. The delayed test showed that negative arousal impaired recollection regardless of picture valence but had no effect on familiarity. Experiment 2 replicated the above findings. Experiment 3 was similar to Experiment 1 except that participants watched a 3-min neutral, negative, or positive video and conducted free recall before the recognition test. Unlike the prior two experiments, the impairment effect of negative arousal disappeared. Experiment 4, where the free recall task was eliminated, replicated the results from Experiment 3. Experiment 5 replicated Experiments 1 and 2 and further showed that the impairment effects of negative arousal could be modulated by delay in emotion induction but not by encoding method or stimuli valence. Taken together, the current study suggests that the enhancement effect observed on words may not generalize to 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。     

情绪效价和唤醒对熟悉性和回想的不同影响

本研究检验了情绪的效价和唤醒对记忆提取阶段熟悉性过程和回想过程的影响及其心理机制。结果发现,编码阶段无分心任务时,积极图片的高、低自信再认准确率均高于消极图片,而唤醒对于高自信再认准确率的影响只限于消极图片;在编码阶段设置分心任务时,发现积极和消极的高唤醒图片的高自信再认准确率显著高于低唤醒图片。这些结果说明情绪的效价影响了熟悉性和回想两类记忆过程,而唤醒只影响回想过程,效价效应是编码阶段被试调用认知资源对积极图片进行精细加工的结果,而唤醒对回想过程的影响是自动编码高唤醒刺激细节的结果。     

Gender differences in the effects of post-learning emotion on consolidation of item memory and source memory

Item memory and source memory are two integral elements of episodic memory. Although many studies have examined the effect of emotion on item memory, little research has simultaneously taken into account item memory and source memory. In addition, in the majority of previous studies, learning stimuli are used as the source of emotion, making it difficult to understand whether emotion has an effect on encoding or on consolidation of episodic memory. Furthermore, although gender differences exist in neurophysiological responses to emotional stimuli, in many studies gender differences were neglected and this leaves the picture incomplete regarding the effect of emotion on episodic memory. In this study, we examined gender differences in the effects of post-learning emotion on consolidation of item memory and source memory. Participants learned neutral Chinese nouns, took a memory pretest, and were then randomly assigned to three conditions, in which they either watched a 3-min negative video clip, or watched a 3-min positive video clip, or remained calm and relaxed for 3 min. Thirty minutes after the initial learning, participants took a memory posttest. We found that: (1) For females, post-learning negative emotion enhanced consolidation of item memory; however, neither negative emotion nor positive emotion had a significant effect on consolidation of source memory; (2) For males, neither negative nor positive emotion after learning had a significant effect on either item memory or source memory. Possible reasons for the gender differences, as well as the theoretical significance and practical implications of this study were discussed.     

Testing emotional memories: does negative emotional significance influence the benefit received from testing?

A large body of research shows that emotionally significant stimuli are better stored in memory. One question that has received much less attention is how emotional memories are influenced by factors that influence memories after the initial encoding of stimuli. Intriguingly, several recent studies suggest that post-encoding factors do not differ in their effects on emotional and neutral memories. However, to date, only detrimental factors have been addressed. In the present study, we examined whether emotionally negative memories are differentially influenced by a well-known beneficial factor: the testing of memories. We employed a standard cued recall testing-effect paradigm where participants studied cue-target pairs for negative and neutral target pictures. In a subsequent post-encoding phase, one third of the cue-target pairs were tested and one third restudied; the remaining third served as control pairs. After one week, memory for all cue-target pairs was tested. While replicating both the testing effect and the emotional enhancement effect, no differences between negative and neutral memories in the benefits received from testing and restudying were observed. Thus, it seems to be true that post-encoding factors do not influence emotional memories in any other way than neutral memories, even when they are beneficial.     

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.     

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.     

Timing matters: Negative emotion elicited 5 min but not 30 min or 45 min after learning enhances consolidation of internal-monitoring source memory

Two experiments examined the time-dependent effects of negative emotion on consolidation of item and internal-monitoring source memory. In Experiment 1, participants (n = 121) learned a list of words. They were asked to read aloud half of the words and to think about the remaining half. They were instructed to memorize each word and its associative cognitive operation (“reading” versus “thinking”). Immediately following learning they conducted free recall and then watched a 3-min either neutral or negative video clip when 5 min, 30 min or 45 min had elapsed after learning. Twenty-four hours later they returned to take surprise tests for item and source memory. Experiment 2 was similar to Experiment 1 except that participants, without conducting an immediate test of free recall, took tests of source memory for all encoded words both immediately and 24 h after learning. Experiment 1 showed that negative emotion enhanced consolidation of item memory (as measured by retention ratio of free recall) regardless of delay of emotion elicitation and that negative emotion enhanced consolidation of source memory when it was elicited at a 5 min delay but reduced consolidation of source memory when it was elicited at a 30 min delay; when elicited at a 45 min delay, negative emotion had little effect. Furthermore, Experiment 2 replicated the enhancement effect on source memory in the 5 min delay even when participants were tested on all the encoded words. The current study partially replicated prior studies on item memory and extends the literature by providing evidence for a time-dependent effect of negative emotion on consolidation of source memory based on internal monitoring.     

Enhanced selective memory consolidation following post-learning pleasant and aversive arousal

It is well established that emotions modulate memory, typically enhancing consolidation through post-learning arousal. However, many aspects of this phenomenon have yet to be delineated. For example, it remains unclear whether or not the type of arousal is relevant (pleasant vs. aversive), whether arousal enhances memory selectively for some stimuli but not others (emotional vs. neutral), which specific aspects of the stimulus representation (gist vs. detail) are affected, and whether these mechanisms are sexually dimorphic. In order to explore these issues, 178 undergraduate participants viewed a series of negative, positive and neutral pictures. They were then subjected to a post-learning arousal manipulation in the form of a pleasantly arousing-, aversively arousing-, or neutral video. Free recall tests one week later indicated that both pleasant and aversive post-learning arousal enhanced memory consolidation for positive and negative but not neutral stimuli, independent of the participants' sex. Further analysis for gist and detail aspects suggests that post-learning arousal enhances memory for the gist of the stimuli. The study has implications for the understanding of healthy and pathological cognitive-affective processes in humans.     

The effect of cognitive reappraisal on long‐term emotional experience and emotional memory

One's ability to properly regulate emotion is critical to psychological and physical well‐being. Among various strategies to regulate emotion, cognitive reappraisal has been shown to modulate both emotional experience and emotional memory. However, most studies of reappraisal have focused on reappraisal of negative situations, with reappraisal of positive emotion receiving considerably less attention. In addition, the effects of reappraisal on emotional reactions to stimuli are typically only assessed either immediately or after a short delay, and it remains unclear whether reappraisal effects persist over longer time periods. We investigated the effect of cognitive reappraisal on emotional reactions and long‐term episodic memory for positive and negative stimuli. Men and women viewed emotionally negative, positive, and neutral pictures while they were instructed to either increase, decrease, or maintain the initial emotional reactions elicited by the pictures. Subjective ratings of emotional valence and arousal were assessed during the regulation task and again after 1 week. Memory for the pictures was assessed with free recall. Results indicated that pictures accompanied by instructions to increase emotion were better recalled than pictures reappraised to decrease emotion. Modulation of emotional arousal elicited by stimuli persisted over a week, but this effect was observed only for men. These findings suggest that cognitive reappraisal can have long‐lasting effects on emotional reactions to stimuli. However, the sex differences observed for the effects of reappraisal on emotional reactions highlight the importance of considering individual differences in the effects of regulation.     

Do emotional stimuli interfere with response inhibition? Evidence from the stop signal paradigm

Participants performed a stop signal task in which an emotional picture preceded a neutral stimulus. They were asked to respond on the basis of the identity of the neutral stimulus unless an auditory tone was presented, in which case participants should try to withhold their response. In Experiment 1, we used positive, neutral and negative pictures. Results demonstrated that the presentation of an emotional stimulus prolonged both response and stopping latencies regardless of the valence of the emotional stimulus. This suggested that the degree of arousal could modulate the interference effect. In Experiment 2, high- and low-arousing pictures with a positive or negative valence were used. In line with the arousal hypothesis, high-arousal pictures interfered more with responding and stopping than low-arousing pictures whereas the valence of the pictures had little or no effect. These findings support the hypothesis that emotional stimuli interrupt ongoing cognitively controlled activities because they attract attention away from these ongoing activities.     

诱发及个体自发认知重评对情绪唤醒反应及情绪记忆的影响

为了明确诱发（IRE）及个体习惯化的自发（SRE）认知重评策略对情绪唤醒反应及情绪记忆的影响,在测量被试SRE水平的基础上,先呈现一系列中性与负性情绪图片,要求被试对图片内容进行自然观看或认知重评,同时记录被试的主观与生理唤醒水平,之后对图片进行自由回忆及再认测试。发现IRE显著降低了情绪唤醒水平及再认正确率,但只对情绪唤醒反应较高的LR（SRE水平较低）被试有效。结果提示,IRE对情绪唤醒反应与情绪记忆的调控受到SRE的影响。     

Emotionally arousing pictures increase blood glucose levels and enhance recall

Arousal enhances memory in human participants and this enhancing effect is likely due to the release of peripheral epinephrine. As epinephrine does not readily enter the brain, one way that peripheral epinephrine may enhance memory is by increasing circulating blood glucose levels. The present study investigated the possibility that emotionally arousing color pictures would improve memory and elevate blood glucose levels in human participants. Blood glucose levels were measured before, 15 min, and 30 min after male university students viewed 60 emotionally arousing or relatively neutral pictures. Participants viewed each picture for 6 s and then had 10 s to rate the arousal (emotional intensity) and valence (pleasantness) of each picture. A free-recall memory test was given 30 min after the last picture was viewed. Although the emotionally arousing and neutral picture sets were given comparable valence ratings, participants who viewed the emotionally arousing pictures rated the pictures as being more arousing, recalled more pictures, and had higher blood glucose levels after viewing the pictures than did participants who viewed the neutral pictures. These findings indicate that emotionally arousing pictures increase blood glucose levels and enhance memory, and that this effect is not due to differences in the degree of pleasantness of the stimuli. These findings support the possibility that increases in circulating blood glucose levels in response to emotional arousal may be part of the biological mechanism that allows emotional arousal to enhance memory.     

The effects of emotion on younger and older adults’ monitoring of learning

Age-related differences in memory monitoring appear when people learn emotional words. Namely, younger adults’ judgments of learning (JOLs) are higher for positive than neutral words, whereas older adults’ JOLs do not discriminate between positive versus neutral words. In two experiments, we evaluated whether this age-related difference extends to learning positive versus neutral pictures. We also evaluated the contribution of two dimensions of emotion that may impact younger and older adults’ JOLs: valence and arousal. Younger and older adults studied pictures that were positive or neutral and either high or low in arousal. Participants made immediate JOLs and completed memory tests. In both experiments, the magnitude of older adults’ JOLs was influenced by emotion, and both younger and older adults demonstrated an emotional salience effect on JOLs. As important, the magnitude of participants’ JOLs was influenced by valence, and not arousal. Emotional salience effects were also evident on participants’ free recall, and older adults recalled as many pictures as did younger adults. Taken together, these data suggest that older adults do not have a monitoring deficit when learning positive (vs. neutral) pictures and that emotional salience effects on younger and older adults’ JOLs are produced more by valence than by arousal.     

情绪性记忆的定向遗忘效应

刺激的情绪性具有增强记忆的效果,那么,带有情绪信息的刺激对遗忘又会产生怎样的影响？已有研究从行为及认知神经机制层面探讨了情绪性刺激对定向遗忘效应的影响,但结果并不一致。总结已有文献发现,以情绪性刺激的材料类型、情绪效价、唤醒度和熟悉度为主的客观因素和以被试的情绪状态为主的主观因素均为影响定向遗忘效应产生及其稳定性的重要原因。这类研究是对有意遗忘研究领域的重要补充,也加深了人们对有意遗忘机制的理解。     

情绪唤醒影响记忆巩固过程的神经生理机制

白鼠和人类都对情绪唤醒的经历有更好的记忆。情绪唤醒影响记忆巩固的神经生理机制主要有以下几种方式:(a)情绪唤醒或急性应激,会引发个体内部应激激素的释放,从而增强其记忆巩固过程。(b1)杏仁核的激活对情绪唤醒影响记忆巩固过程十分重要,杏仁核内部去甲肾上腺素(NE)的释放影响记忆巩固过程。(b2)杏仁核投射到负责不同类型记忆加工的脑区,如海马和皮层,从而影响记忆。(c)应激激素影响记忆巩固的过程中,杏仁核内NE的激活在这一过程中扮演着重要角色。综上,情绪唤醒影响记忆巩固的过程,涉及到激素调节、神经调节及二者的共同作用。     

来源记忆中背景的情绪效价与唤醒对提取过程的影响

以往研究表明情绪背景对来源记忆存在影响,但背景的情绪效价和唤醒如何影响熟悉性及回想尚存争议。本研究以ERPs技术作为测量手段,采用来源记忆多键范式,操纵背景的情绪效价及唤醒强度,以探讨编码阶段背景情绪影响来源记忆提取的认知神经机制。学习阶段,呈现中性汉字及情绪图片（正性高唤醒、正性低唤醒、负性高唤醒、负性低唤醒）;测验阶段,仅呈现汉字,被试进行五键判断。行为结果发现：来源正确的比率比来源错误的比率更高,反应时更短;同时提取正性背景的辨别力更强,反应时更短;提取高唤醒背景反应时更短。脑电结果发现了分别代表熟悉性及回想的FN400及LPC新旧效应,且在500～700 ms,提取正性背景及高唤醒背景诱发显著更正的ERPs,但效价与唤醒没有交互作用。总体来说,来源记忆中背景效价及唤醒度对回想过程存在独立影响,体现为正性背景及高唤醒背景对来源提取的促进作用。     

Emotional enhancement of immediate memory: Positive pictorial stimuli are better recognized than neutral or negative pictorial stimuli

We examined emotional memory enhancement (EEM) for negative and positive pictures while manipulating encoding and retrieval conditions. Two groups of 40 participants took part in this study. Both groups performed immediate implicit (categorization task) and explicit (recognition task) retrieval, but for one group the tasks were preceded by incidental encoding and for the other group by intentional encoding. As indicated by the sensitivity index (d'), after incidental encoding positive stimuli were easier to recognize than negative and neutral stimuli. Participants' response criterion was more liberal for negative stimuli than for both positive and neutral ones, independent of encoding condition. In the implicit retrieval task, participants were slower in categorizing positive than negative and neutral stimuli. However, the priming effect was larger for emotional than for neutral stimuli. These results are discussed in the context of the idea that the effect of emotion on immediate memory enhancement may depend on the intentionality to encode and retrieve information.