The effect of arousal on memory for emotionally-relevant information: a study of skydivers

The aim of the present study was to test memory for information under conditions of extreme arousal in an analogue design to mimic hyperarousal during trauma exposure. Prior to their skydive, 70 novice skydivers were administered measures of fear, heart rate, and anxiety sensitivity. Half the participants learnt a list of words that varied in both relevance to their skydive and valence (irrelevant/relevant, negative/neutral) on the plane (skydivers), and remaining participants learnt an identical list of words on the ground (delayed controls). Following the skydive, participants completed free recall and recognition tasks; heart rate, dissociation, and subjective arousal were also measured. Consistent with an attentional narrowing hypothesis, skydivers recalled comparable a comparable number of relevant words as delayed controls, but significantly less irrelevant words. In terms of recognition performance, skydivers displayed better recognition of relevant words but poorer recognition of irrelevant words than delayed controls. Valence of words did not alter the pattern of results. The implications of the findings are discussed in the context of understanding memory processes under conditions of high threat.     

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.     

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.     

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。     

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。     

Recognition of emotional pictures: Behavioural and electrophysiological measures

The effects of emotional content of images on recognition memory were studied, bringing together electrophysiological (Event-Related brain Potentials, ERPs) and behavioural (accuracy and speed of recognition, and remember/know judgements) indices. In the study phase, participants assessed 120 images on the scales of valence and arousal. In the test phase, ERPs were recorded while participants viewed again the images, put together with 120 new, and were asked to make old/new decisions and remember/know judgements on them. A clear arousal bias was obtained for remember/know judgements, which revealed that correctly recognised arousing images (negative and positive) received more remember judgements than nonarousing images (neutral and relaxing). Moreover, a Late Positive Component (LPC) activation revealed an old/new effect enhanced by arousing images. The LPC activation was located in parietal areas (precuneus), which appears to be mostly related to successful retrieval based on recollection. The results obtained through different indices supported the emotional bias found in previous studies for arousing material, but do not clarify the effect of the emotional valence on recognition.     

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).     

Effects of pre-learning stress on memory for neutral, positive and negative words: Different roles of cortisol and autonomic arousal

Stress can have enhancing or impairing effects on memory. Here, we addressed the effect of pre-learning stress on subsequent memory and asked whether neutral and emotionally valent information are differentially affected by specific stress components, autonomic arousal and stress-induced cortisol. Ninety-six healthy men and women underwent either a stressor (modified cold pressor test) or a control warm water exposure. During stress, participants showed comparable autonomic arousal (heart rate, blood pressure), while 60 percent showed an increase of cortisol (responders vs. 40 percent non-responders). Ten minutes after the cold pressor test neutral, positive and negative words were presented. Free recall was tested 1 and 24 h later. Overall, positive and negative words were better recalled than neutral words. Stress enhanced the recall of neutral words independently of cortisol response. In contrast, the free recall of negative words was enhanced in cortisol responders in the 1-h but not 24-h test which might suggest different effects of cortisol on consolidation and reconsolidation processes. Recall for positive words was unaffected by stress-induced cortisol. To summarize, (i) pre-learning stress can enhance memory for neutral words independently of cortisol and (ii) stress effects on memory for negative words appear to rely on stress-induced cortisol elevations, the absence of this effect for positive words might be at least partly due to differences in arousal evoked by positive vs. negative words.     

Distinct parietal sites mediate the influences of mood,arousal, and their interaction on human recognition memory

The two dimensions of emotion, mood valence and arousal, have independent effects on recognition memory. At present, however, it is not clear how those effects are reflected in the human brain. Previous research in this area has generally dealt with memory for emotionally valenced or arousing stimuli, but the manner in which interacting mood and arousal states modulate responses in memory substrates remains poorly understood. We investigated memory for emotionally neutral items while independently manipulating mood valence and arousal state by means of music exposure. Four emotional conditions were created: positive mood/high arousal, positive mood/low arousal, negative mood/high arousal, and negative mood/low arousal. We observed distinct effects of mood valence and arousal in parietal substrates of recognition memory. Positive mood increased activity in ventral posterior parietal cortex (PPC) and orbitofrontal cortex, whereas arousal condition modulated activity in dorsal PPC and the posterior cingulate. An interaction between valence and arousal was observed in left ventral PPC, notably in a parietal area distinct from the those identified for the main effects, with a stronger effect of mood on recognition memory responses here under conditions of relative high versus low arousal. We interpreted the PPC activations in terms of the attention-to-memory hypothesis: Increased arousal may lead to increased top-down control of memory, and hence dorsal PPC activation, whereas positive mood valence may result in increased activity in ventral PPC regions associated with bottom-up attention to memory. These findings indicate that distinct parietal sites mediate the influences of mood, arousal, and their interplay during recognition memory.     

Brief,pre-retrieval stress differentially influences long-term memory depending on sex and corticosteroid response

Previous work has indicated that stress generally impairs memory retrieval. However, little research has addressed discrepancies that exist in this line of work and the factors that could explain why stress can exert differential effects on retrieval processes. Therefore, we examined the influence of brief, pre-retrieval stress that was administered immediately before testing on long-term memory in males and females. Participants learned a list of 42 words varying in emotional valence and arousal. Following the learning phase, participants were given an immediate free recall test. Twenty-four hours later, participants submerged their non-dominant hand in a bath of ice cold (Stress) or warm (No Stress) water for 3 min. Immediately following this manipulation, participants’ memory for the word list was assessed via free recall and recognition tests. We observed no group differences on short-term memory. However, male participants who showed a robust cortisol response to the stress exhibited enhanced long-term recognition memory, while male participants who demonstrated a blunted cortisol response to the stress exhibited impaired long-term recall and recognition memory. These findings suggest that the effects of brief, pre-retrieval stress on long-term memory are sex-specific and mediated by corticosteroid mechanisms.     

The moderating effects of stimulus valence and arousal on memory suppression

This study examined the separate and combined effects of stimulus valence and arousal on retrieval inhibition. Participants performed Anderson and Green's (2001) memory suppression task with stimuli varying across dimensions of valence and arousal. Memory was tested through free and cued recall as well as speeded recognition. Results showed that both stimulus valence and arousal influenced the extent to which participants successfully inhibited retrieval, but not in the ways anticipated. Specifically, the strongest inhibition effects were for highly arousing, pleasant words. In addition, unpleasant stimuli that were suppressed were better recalled during both cued and free-recall tasks than pleasant stimuli that were suppressed. Across all tests of memory performance, there were no significant differences between the experimental conditions for highly arousing, unpleasant words. The implications of these findings are discussed.     

Old Fears Die Hard: Return of Public Speaking Fear in a Virtual Reality Procedure

Exposure-based therapy is an effective treatment for social anxiety, but some patients relapse. We used a novel virtual reality procedure to examine spontaneous recovery (i.e., a return of fear over time) and fear renewal (i.e., the return of fear after a context switch) in individuals with fear of public speaking. On Day 1, 32 participants received exposure training before a virtual audience. On Day 8, participants completed a spontaneous recovery phase, followed by a fear renewal test, in which they gave a presentation in front of a new (context switch) or the same audience (no context switch). After exposure, participants exhibited a lower heart rate, subjective distress, negative valence, and arousal. One week later, participants showed spontaneous recovery of heart rate, and the context switch group showed renewal of subjective distress, negative valence, and arousal. Future studies can use this procedure to test interventions aimed at improving long-term exposure effects in individuals with public speaking fear.     

Neurophysiological indices of free recall memory biases in major depression: The impact of stimulus arousal and valence

This study examined differential impact of the valence and arousal characteristics of stimuli on memory biases and brain activity in major depressive disorder (MDD) and non-depressed control participants. P300 and slow wave (SW) components of the event-related brain potential (ERP) were recorded in 18 MDD and 18 control individuals during the encoding of positive and negative, high and low arousal words in a free recall task. Control participants demonstrated expected enhanced memory for positive stimuli that was accompanied by a corresponding increase in SW ERP components. These effects were not seen in the MDD participants. Rather, memory biases for negative information in MDD were only observed for low arousal words and were not reflected in ERP amplitudes. This study suggests that the inconsistency in the MDD memory bias literature may be related to the arousing nature of the stimuli incorporated in the study.     

The importance of identifying underlying process abnormalities in alexithymia: Implications of the three-process model and a single case study illustration

We present an in-depth case study of a rare individual (whom we will refer to as “Jane”) who reported an inability to experience emotion. Jane completed a range of assessments measuring alexithymia, emotional awareness, and emotion recognition ability. She, along with 22 control participants, also underwent skin conductance (SC) measurement and facial electromyography (EMG) during exposure to affective images, and self reported the valence/arousal of their responses to those images. Jane scored high on alexithymia and low on emotional awareness; yet she performed well on emotion recognition measures and showed a typical pattern of valence ratings. Her SC responses and subjective arousal ratings were atypically low, and some of her EMG responses were also atypical. Jane’s deficit profile highlights the dissociability of self-focused emotional awareness and other-focused emotion recognition ability, as well as the dissociability between the generation and representation of valence and arousal (with both subjective and objective measures).     

An increase in stimulus arousal has differential effects on the processing speed of pleasant and unpleasant stimuli

The arousal value of a stimulus influences its salience, whereby higher arousal should lead to faster processing. However, in previous research, participants consistently made faster valence judgments for low arousal, pleasant stimuli than for high arousal, pleasant stimuli. The speed of valence and arousal judgments for pictures and words were investigated in three experiments. Valence judgments were faster for low arousal than for high arousal pleasant pictures and for high arousal than for low arousal unpleasant pictures and words. Moreover, arousal judgments were faster for low arousal than high arousal pleasant and for high arousal than low arousal unpleasant pictures and words. The current research confirms that the impact of valence and arousal on processing speed does not reflect on the labels (valence versus arousal) used when recording speeded judgments. Similarly to valence, stimulus arousal interacts differentially with the evaluation of pleasant and unpleasant stimuli producing a processing advantage for high arousal, unpleasant stimuli but not high arousal, pleasant stimuli.     

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。     

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.     

“Passion” versus “patience”: the effects of valence and arousal on constructive word recognition

Accumulating evidence suggests that emotional information is often recognised faster than neutral information. Several studies examined the effects of valence and arousal on word recognition, but yielded partially diverging results. Here, we used two alternative versions of a constructive recognition paradigm in which a target word is hidden by a visual mask that gradually disappears, to investigate whether the emotional properties of words influence their speed of recognition. Participants were instructed either to classify the incrementally appearing word as emotional or non-emotional (semantic categorisation task) or to decide whether the appearing letter string is an existing word or not (lexical decision task). Results from both tasks revealed faster recognition times for high- compared to low-arousing words, and for positive compared to negative or neutral words. These findings indicate a recognition advantage for emotionally positive and highly arousing stimuli that persists even when visual word recognition is hampered and participants are encouraged to make more active, semantic inferences to generate the meaning of the emerging word.     

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。     

Mood effects on attentional control: a preregistered replication study and critical analysis

In a widely cited paper, Jefferies et al. (2008) report a study in which they manipulated participants’ mood and examined the effects of this manipulation on their performance on the Attentional Blink task. Their results revealed an interaction between emotional valence and arousal: attentional control of participants who experienced a negative mood with low arousal (i.e. sadness) was best, whereas it was worst for participants who experienced a negative mood with high arousal (i.e. anxiety). Performance for participants who were in a positive mood, either with low arousal (i.e. calmness) or high arousal (i.e. happiness) had intermediate scores. In this study, I examined the replicability of this effect and performed additional analyses to investigate the extent to which this effect is due to perceptual or attentional processes and to examine the role of distraction on AB performance. Importantly, the results showed that the crucial interaction between emotional valence and arousal did not reach significance. This could be due a diversity of factors that are addressed in the discussion.