Post-encoding emotional arousal enhances consolidation of item memory,but not reality-monitoring source memory

The current study examined whether the effect of post-encoding emotional arousal on item memory extends to reality-monitoring source memory and, if so, whether the effect depends on emotionality of learning stimuli and testing format. In Experiment 1, participants encoded neutral words and imagined or viewed their corresponding object pictures. Then they watched a neutral, positive, or negative video. The 24-hour delayed test showed that emotional arousal had little effect on both item memory and reality-monitoring source memory. Experiment 2 was similar except that participants encoded neutral, positive, and negative words and imagined or viewed their corresponding object pictures. The results showed that positive and negative emotional arousal induced after encoding enhanced consolidation of item memory, but not reality-monitoring source memory, regardless of emotionality of learning stimuli. Experiment 3, identical to Experiment 2 except that participants were tested only on source memory for all the encoded items, still showed that post-encoding emotional arousal had little effect on consolidation of reality-monitoring source memory. Taken together, regardless of emotionality of learning stimuli and regardless of testing format of source memory (conjunction test vs. independent test), the facilitatory effect of post-encoding emotional arousal on item memory does not generalize to reality-monitoring source memory.     

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。     

A Novel Demonstration of Enhanced Memory Associated with Emotional Arousal

The relationship between emotional arousal and long-term memory is addressed in two experiments in which subjects viewed either a relatively emotionally neutral short story (presented as a brief slide show) or a closely matched but more emotionally arousing story and were tested for retention of the story 2 weeks later. Experiment 1 provides essential replication of the results of Heuer and Reisberg (1990) and illustrates the common interpretive problem posed by the use of different stimuli (slides) in the neutral versus emotional stories. In Experiment 2, identical slides (and sequence) were used in both the neutral and arousal stores. Two different stories were created by varying the narration that accompanied each slide. In both experiments, subjects who viewed the arousal story both experienced a greater emotional reaction to the story than did the subjects who viewed the neutral story, and subsequently exhibited enhanced memory for the story. Subjects in Experiment 2 who viewed the arousal story also recalled more slides than did the subjects who viewed the neutral story. This effect was greatest for story phase 2, the phase in which the emotional slide narration occurred. Because this enhanced retention of the story slides cannot be explained by any differences in the slides themselves, the results provide new evidence to support the contention that emotional arousal influences long-term memory in normal human subjects.     

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.     

The role of attention and relatedness in emotionally enhanced memory

Examining the positive and negative pictures separately revealed that emotionally enhanced memory (EEM) for positive pictures was mediated by attention, with no significant influence of emotional arousal, whereas the reverse was true of negative pictures. Consistent with this finding, in Experiment 2 EEM for negative pictures was found even when task emphasis was manipulated so that equivalent attention was allocated to negative and neutral pictures. The results show that attention and semantic relatedness contribute to EEM, with the extent varying with emotional valence. Negative emotion can influence memory independently of these 2 factors.     

Emotional stimuli, divided attention, and memory

The emotion-memory literature has shown that negative emotional arousal enhances memory. S. A. Christianson (1992) proposed that preattentive processing could account for this emotion-memory relationship. Two experiments were conducted to test Christianson's theory. In Experiment 1, participants were exposed to neutral and negative arousing slides. In Experiment 2, participants were exposed to neutral, negative arousing, and positive arousing slides. In both experiments, the aforementioned variable was factorially combined with a divided-attention or non-divided-attention condition. The authors predicted that, in contrast to the nondivided condition, dividing attention would adversely impact neutral and positive stimuli more than negative stimuli. The hypothesis was supported; participants recalled more high negative-arousal slides than positive or neutral slides when their attention was divided rather than nondivided.     

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.     

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.     

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.     

Positive emotion can protect against source memory impairment

Despite widespread belief that memory is enhanced by emotion, evidence also suggests that emotion can impair memory. Here we test predictions inspired by object-based binding theory, which states that memory enhancement or impairment depends on the nature of the information to be retrieved. We investigated emotional memory in the context of source retrieval, using images of scenes that were negative, neutral or positive in valence. At study each scene was paired with a colour and during retrieval participants reported the source colour for recognised scenes. Critically, we isolated effects of valence by equating stimulus arousal across conditions. In Experiment 1 colour borders surrounded scenes at study: memory impairment was found for both negative and positive scenes. Experiment 2 used colours superimposed over scenes at study: valence affected source retrieval, with memory impairment for negative scenes only. These findings challenge current theories of emotional memory by showing that emotion can impair memory for both intrinsic and extrinsic source information, even when arousal is equated between emotional and neutral stimuli, and by dissociating the effects of positive and negative emotion on episodic memory retrieval.     

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.     

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.     

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.     

Effects of sexual versus fear arousal on alcohol consumption in college males

To compare the effects of pleasant and aversive arousal on alcohol consumption, 18 male undergraduates had three weekly sessions to separately view erotic, mutilation or neutral slides in a simulated memory experiment. Following exposure to the slides, they received access to alcoholic and nonalcoholic beverages, which were presented to half the subjects in a taste rating task, and to half as the result of engaging in an operant lever-press task. Subjects believed these tasks to be distractors during a purported retention interval. Self-report instruments and basal skin conductance confirmed the success of the affective manipulations. However, only the subjects using the taste task after viewing erotic slides significantly increased alcohol consumption. These results question a tension reduction model of drinking and qualify the contribution of autonomic arousal to motivation for drinking.     

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.     

Effects of test sequence on anterograde and retrograde impairment of negative emotional scenes1

Abstract: The present study examined recognition for sequences of scenes depicting emotional compared with neutral events. In two experiments, participants were presented with a thematic series of 18 slides of scenes in which the content of two critical scenes in the middle of the series were either emotional (dead men's bodies) or neutral (an opera). A two‐item, forced‐choice recognition paradigm was used to test participants’ immediate memory performance of all 18 slides of scenes. In Experiment 1, anterograde and retrograde amnesic effects were observed for the emotional, but not the neutral scenes when a test sequence of scenes was used that did not match the original presentation order. In contrast, in Experiment 2 the test sequence matched the order seen during the original presentation, and both the anterograde and retrograde amnesic effects were not found. These results indicate that the reinstatement of the original event context is an important factor for the recognition of negative emotional memories.     

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。     

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。     

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。