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.     

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。     

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.     

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.     

Different confidence-accuracy relationships for feature-based and familiarity-based memories

Participants studied naturalistic pictures presented for varying brief durations and then received a recognition test on which they indicated whether each picture was old or new and rated their confidence. In 1 experiment they indicated whether each "old"/"new" response was based on memory for a specific feature in the picture or instead on the picture's general familiarity; in another experiment, we defined pictures that tended to elicit feature versus familiarity responses. Thus, feature/familiarity was a dependent variable in 1 experiment and an independent variable in the other. In both experiments feature-based responses were more accurate than those that were familiarity based, and confidence and accuracy increased with duration for both response types. However, when confidence was controlled for, mean accuracy was higher for familiarity-based than for feature-based responses. The theoretical implication is that confidence and accuracy arise from different underlying information. The applied implication is that confidence differences should not be taken as implying accuracy differences when the phenomenal basis of the memory reports differ.     

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.     

The effects of conformity on recognition judgements for emotional stimuli

Exposure to another’s account of a shared event can influence the content of an individual’s memory report. We examine whether the emotionality of the to-be-remembered information influences the likelihood that socially encountered post-event information is accepted into memory. Participants were exposed to positive, negative or neutral emotional pictures. Subsequently, they had to discriminate these pictures from new pictures in a ‘yes/no’ recognition decision either before or subsequent to a confederate providing misinformation, accurate or no information. Post-event information influenced participants’ responding in the recognition test. Effects were larger for participants viewing neutral items and persisted for these items on a subsequent private source monitoring test. These findings indicate that people rely more on information from others when encountering non-emotional compared to emotional items. We suggest that increased memory strength in conjunction with access to strong retrieval cues in the recognition test serves to shield emotional items from vulnerability to effects of memory conformity.     

The medial temporal lobe and the attributes of memory

Neuroimaging and lesion studies have seemed to converge on the idea that the hippocampus selectively supports recollection. However, these studies usually involve a comparison between strong recollection-based memories and weak familiarity-based memories. Studies that avoid confounding memory strength with recollection and familiarity almost always find that the hippocampus supports both recollection and familiarity. We argue that the functional organization of the medial temporal lobe (MTL) is unlikely to be illuminated by the psychological distinction between recollection and familiarity and will be better informed by findings from neuroanatomy and neurophysiology. These findings indicate that the different structures of the MTL process different attributes of experience. By representing the widest array of attributes, the hippocampus supports recollection-based and familiarity-based memory of multiattribute stimuli.     

The effect of emotional stress on involuntary and voluntary conscious memories

Clinical theories of post-traumatic stress disorder often claim that intrusive (involuntary) memories favour emotionally stressful material and that these memories come with more sensory imagery and emotional reliving compared to voluntary memories. However, these assumptions have not been verified experimentally. Here we obtained recordings of emotional reactions to aversive pictures at the time of encoding, as well as records of involuntary and voluntary memories of these pictures in a subsequent diary study. A comparison of individual ratings, obtained during encoding, of pictures recalled involuntarily and voluntarily showed that emotional stress at encoding increased overall accessibility, independent of whether recall was voluntary or involuntary. However at the time of recall, voluntary memories scored higher on narrative content and on measures of imagery. The findings are compatible with research on emotion and memory in general, but challenge clinical claims of differential involuntary versus voluntary access to emotionally stressful events.     

预期错误与急性应激对不同强度恐惧记忆提取消退的影响

在条件性恐惧记忆再巩固模型下, 预期错误被证明是引发记忆不稳定的必要条件, 但其在不同强度恐惧记忆下的作用尚不明确。对于高强度可能导致的提取无效, 缺乏相应的探索以寻找解决办法, 而应激(stress)在其中发挥的作用值得探索。本研究考察人类被试中, 预期错误在不同强度恐惧记忆下的作用, 以及提取之后施加外源性应激对于消退进程的影响。结果发现, 对于较弱的恐惧记忆, 单个预期错误提取后消退可显著抑制恐惧自发恢复; 而对于较强恐惧记忆, 单个预期错误不能提取恐惧记忆进入再巩固, 已消退的记忆还会复发; 且在该种情况下, 如果在提取后施加外源性急性应激, 会进一步增大恐惧恢复。     

Blurring of emotional and non-emotional memories by taxing working memory during recall

Memories that are recalled while working memory (WM) is taxed, e.g., by making eye movements (EM), become blurred during the recall + EM and later recall, without EM. This may help to explain the effects of Eye Movement and Desensitisation and Reprocessing (EMDR) in the treatment of post-traumatic stress disorder (PTSD) in which patients make EM during trauma recall. Earlier experimental studies on recall + EM have focused on emotional memories. WM theory suggests that recall + EM is superior to recall only but is silent about effects of memory emotionality. Based on the emotion and memory literature, we examined whether recall + EM has superior effects in blurring emotional memories relative to neutral memories. Healthy volunteers recalled negative or neutral memories, matched for vividness, while visually tracking a dot that moved horizontally (“recall + EM”) or remained stationary (“recall only”). Compared to a pre-test, a post-test (without concentrating on the dot) replicated earlier findings: negative memories are rated as less vivid after “recall + EM” but not after “recall only”. This was not found for neutral memories. Emotional memories are more taxing than neutral memories, which may explain the findings. Alternatively, transient arousal induced by recall of aversive memories may promote reconsolidation of the blurred memory image that is provoked by EM.     

Confidence–accuracy relations for faces and scenes: Roles of features and familiarity

Using naturalistic scenes, we recently demonstrated that confidence?Caccuracy relations differ depending on whether recognition responses are based on memory for a specific feature or instead on general familiarity: When confidence is controlled for, accuracy is higher for familiarity-based than for feature-based responses. In the present experiment, we show that these results generalize to face recognition. Subjects studied photographs of scenes and faces presented for varying brief durations and received a recognition test on which they (1) indicated whether each picture was old or new, (2) rated their confidence in their response, and (3) indicated whether their response was based on memory for a feature or on general familiarity. For both stimulus types, subjects were more accurate and more confident for their feature-based than for their familiarity-based responses. However, when confidence was held constant, accuracy was higher for familiarity-based than for feature-based responses. These results demonstrate an important similarity between face and scene recognition and show that for both types of stimuli, confidence and accuracy are based on different information.     

False recognition of emotional stimuli is lateralised in the brain: An fMRI study

We have investigated whether the left (LH) and right (RH) hemisphere play a different role in eliciting false recognition (FR) and whether their involvement in this memory illusion depends on the emotional content of stimuli. Negative and neutral pictures (taken from IAPS) were presented in the divided-visual field paradigm. Subjects task was to indicate whether the pictures had already been presented or not during the preceding study phase. FR rate was much higher for the RH than the LH presentations. In line, FR resulted in activations mainly in the right prefrontal cortex (PFC) for either RH or LH presentations. Emotional content of stimuli facilitated the formation of false memories and strengthened the involvement of the right PFC in FR induction.     

ROC curves and confidence judgements in recognition memory

Most models of recognition memory rely on a strength/familiarity-based signal detection account that assumes that the processes giving rise to a confidence judgment are the same as those giving rise to an old-new decision. Confidence is assumed to be scaled directly from the perceived familiarity of a probe. This assumption was tested in 2 experiments that examine the shape of confidence-based z receiver operating characteristic (zROC) curves under different levels of response bias induced by changing stimulus probabilities (Experiment 1) and payoffs (Experiment 2). Changes in the shape of the zROC curves with bias indicate that confidence is not scaled directly from perceived familiarity or likelihood. A model of information accumulation in recognition memory is proposed that can account for the observed effects.     

The tenacious nature of memory binding for arousing negative items

In two experiments, we investigated whether people are better or worse at updating memory for the location of emotional pictures than of neutral pictures. We measured participants’ memories for the locations of both arousing negative pictures and neutral pictures while manipulating practice (encountering the same event repeatedly) and interference (encountering the same picture in a different location). Memory for the context of emotional items was less likely to be corrected when erroneous and was less likely to be correctly updated when the context changed. These results suggest that initial item-context binding is more tenacious for emotional items than for neutral items, even when such binding is incorrect.     

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.     

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。     

压抑遗忘的影响因素

人在生活中的一些负性经历或无效信息可以通过压抑提取而遗忘,这种遗忘称为压抑遗忘。压抑遗忘不仅受压抑时长、压抑次数、实验材料的情绪效价和唤醒度、期待效应等的影响,还受个体的年龄和精神障碍等的影响。今后应着重考察精神疾病个体记忆控制网络内的连接强度与压抑遗忘的关系,澄清压抑遗忘是否存在补偿机制。     

压抑遗忘的影响因素

人在生活中的一些负性经历或无效信息可以通过压抑提取而遗忘,这种遗忘称为压抑遗忘。压抑遗忘不仅受压抑时长、压抑次数、实验材料的情绪效价和唤醒度、期待效应等的影响,还受个体的年龄和精神障碍等的影响。今后应着重考察精神疾病个体记忆控制网络内的连接强度与压抑遗忘的关系,澄清压抑遗忘是否存在补偿机制。     

The differential effects of emotional salience on direct associative and relational memory during a nap

Relational memories are formed from shared components between directly learned memory associations, flexibly linking learned information to better inform future judgments. Sleep has been found to facilitate both direct associative and relational memories. However, the impact of incorporating emotionally salient information into learned material and the interaction of emotional salience and sleep in facilitating both types of memory is unknown. Participants encoded two sets of picture pairs, with either emotionally negative or neutral objects paired with neutral faces. The same objects were present in both sets, paired with two different faces across the sets. Baseline memory for these directly paired associates was tested immediately after encoding, followed by either a 90-min nap opportunity or wakefulness. Five hours after learning, a surprise test assessed relational memory, the indirect association between two faces paired with the same object during encoding, followed by a retest of direct associative memory. Overall, negative information was remembered better than neutral for directly learned pairs. A nap facilitated both preservation of direct associative memories and formation of relational memories, compared to remaining awake. Interestingly, however, this sleep benefit was observed specifically for neutral directly paired associates, while both neutral and negative relational associations benefitted from a nap. Finally, REM sleep played opposing roles in neutral direct and relational associative memory formation, with more REM sleep leading to forgetting of direct associations but promoting relational associations, suggesting that, while not benefitting memory consolidation for directly learned details, REM sleep may foster the memory reorganization needed for relational memory.