Working memory affects false memory production for emotional events

Whereas a link between working memory (WM) and memory distortions has been demonstrated, its influence on emotional false memories is unclear. In two experiments, a verbal WM task and a false memory paradigm for negative, positive or neutral events were employed. In Experiment 1, we investigated individual differences in verbal WM and found that the interaction between valence and WM predicted false recognition, with negative and positive material protecting high WM individuals against false remembering; the beneficial effect of negative material disappeared in low WM participants. In Experiment 2, we lowered the WM capacity of half of the participants with a double task request, which led to an overall increase in false memories; furthermore, consistent with Experiment 1, the increase in negative false memories was larger than that of neutral or positive ones. It is concluded that WM plays a critical role in determining false memory production, specifically influencing the processing of negative material.     

The influence of training task stimuli on transfer effects of working memory training in aging

IntroductionWorking memory (WM) training is known to produce benefits in older adults’ WM. Transfer effects to untrained abilities, however, remain controversial and several aspects are thought to influence the generalization of benefits, including the kind of stimuli used in the training tasks, an aspect rarely addressed in older adults.ObjectiveThe present study had two aims: (1) to test the efficacy of a visuospatial WM training procedure in older adults, in terms of specific and transfer effects; (2) to examine in two experiments whether the type of stimuli used in the training task influences the training's effectiveness. Experiment 1 adopted images with a neutral valence while experiment 2 used emotionally positive images based on evidence that older adults tend to remember positive stimuli better. In both experiments, specific training-related gains in a visuospatial WM task (the criterion task) and transfer effects on measures of verbal WM, visuospatial short-term memory, processing speed and reasoning were examined. Maintenance of training benefits was also assessed at an 8-month follow-up.MethodSeventy older adult (63–75 years old) volunteers (35 for experiment 1, and 35 for experiment 2) were randomly assigned to a training or active control group. The same visuospatial WM training procedure was used in both experiments, manipulating only the type of stimuli used (neutral in experiment 1 and emotionally positive in experiment 2).ResultsIn both experiments, only trained participants showed specific benefits in the WM criterion task. These gains were also maintained at the follow-up, but no transfer effects were identified.ConclusionOverall, our findings using the present visuospatial WM training paradigm suggest that it is less effective, in terms of transfer effects, than the same paradigm administered verbally in a previous study, regardless of the type of stimuli used in WM training tasks (neutral or emotionally positive stimuli).     

无关工作记忆表征的负性情绪信息能否捕获视觉注意?一项眼动研究

研究通过分析视觉搜索任务的首次注视点和行为反应时, 探讨无关工作记忆表征的负性情绪信息对视觉注意选择的影响。实验1发现在反映早期注意选择的首次注视点百分率指标上, 不管工作记忆表征的情绪效价如何, 均出现了显著的注意捕获效应; 实验2发现当采用中性情绪靶子刺激时, 首次注视点百分率指标上仍表现出了稳健的注意捕获效应; 在首次注视点持续时间指标上, 实验1和实验2均发现记忆匹配条件的干扰刺激显著小于控制条件的干扰刺激, 表现出注意的快速脱离; 而在行为反应时指标上, 早期的注意捕获效应消失(实验1), 甚至被反转为注意抑制效应(实验2)。这些结果表明在早期注意选择阶段, 记忆驱动的注意捕获效应不受工作记忆表征情绪效价的影响, 但认知控制会在早期注意捕获之后促使注意快速脱离记忆匹配的干扰刺激, 其作用效果受靶子刺激情绪效价的调节。     

Updating positive and negative stimuli in working memory in depression

Difficulties in the ability to update stimuli in working memory (WM) may underlie the problems with regulating emotions that lead to the development and perpetuation of mood disorders such as depression. To examine the ability to update affective material in WM, the authors had diagnosed depressed and never-disordered control participants perform an emotion 2-back task in which participants were presented with a series of happy, sad, and neutral faces and were asked to indicate whether the current face had the same (match-set) or different (break-set or no-set) emotional expression as that presented 2 faces earlier. Participants also performed a 0-back task with the same emotional stimuli to serve as a control for perceptual processing. After transforming reaction times to control for baseline group differences, depressed and nondepressed participants exhibited biases in updating emotional content that reflects the tendency to keep negative information and positive information, respectively, active in WM. Compared with controls, depressed participants were both slower to disengage from sad stimuli and faster to disengage from happy facial expressions. In contrast, nondepressed controls took longer to disengage from happy stimuli than from neutral or sad stimuli. These group differences in reaction times may reflect both protective and maladaptive biases in WM that underlie the ability to effectively regulate negative affect.     

Affective bias in visual working memory is associated with capacity

How does the affective nature of task stimuli modulate working memory (WM)? This study investigates whether WM maintains emotional information in a biased manner to meet the motivational principle of approaching positivity and avoiding negativity by retaining more approach-related positive content over avoidance-related negative content. This bias may exist regardless of individual differences in WM functionality, as indexed by WM capacity (overall bias hypothesis). Alternatively, this bias may be contingent on WM capacity (capacity-based hypothesis), in which a better WM system may be more likely to reveal an adaptive bias. In two experiments, participants performed change localisation tasks with emotional and non-emotional stimuli to estimate the number of items that they could retain for each of those stimuli. Although participants did not seem to remember one type of emotional content (e.g. happy faces) better than the other type of emotional content (e.g. sad faces), there was a significant correlation between WM capacity and affective bias. Specifically, participants with higher WM capacity for non-emotional stimuli (colours or line-drawing symbols) tended to maintain more happy faces over sad faces. These findings demonstrated the presence of a “built-in” affective bias in WM as a function of its systematic limitations, favouring the capacity-based hypothesis.     

任务无关情绪刺激对工作记忆信息更新的影响:来自ERP的证据

任务无关的情绪刺激如何对工作记忆的信息更新过程产生影响还不清楚。本研究采用情绪N-back任务,结合事件相关电位技术调查情绪对工作记忆信息更新的影响。ERP结果显示,在0-back任务中,负性分心物诱发的P3显著小于中性分心物,表明其干扰了工作记忆信息更新过程;而在2-back任务中,负性分心物诱发的P3与中性分心物没有显著差异,表明其未对信息更新表现出干扰效应。该结果支持了情绪与认知加工的双竞争模型。     

Distinguishing between automaticity and attention in the processing of emotionally significant stimuli

There is contradicting evidence as to whether irrelevant but significant emotional stimuli can be processed outside the focus of attention. In the current study, participants were asked to ignore emotional and neutral pictures while performing a competing task. In Experiment 1, orienting of attention to distracting pictures was manipulated via a peripheral cue. In Experiment 2, attentional load was varied, either leaving spare attention to process the distracting pictures or, alternatively, depleting attentional resources. Although all pictures were task irrelevant, negative pictures were found to interfere more with performance in comparison to neutral pictures. This finding suggests that processing of negative stimuli is automatic in the sense that it does not require execution of conscious monitoring. However, interference occurred only when sufficient attention was available for picture processing. Hence, processing of negative pictures was dependent on sufficient attentional resources. This suggests that processing of emotionally significant stimuli is automatic yet requires attention.     

Affective valence of words impacts recall from auditory working memory

Abstract

There is limited evidence on the influence of affective stimuli on auditory working memory. The reported study investigated whether emotional auditory words interfere with ongoing auditory processing of words in auditory working memory. On each trial, words with negative, neutral, and positive affective valence were simultaneously presented on three different speakers. Participants recalled the word presented from the centre speaker first and then recalled the words presented from the side speakers. More negative and positive words compared to neutral words were recalled from the centre speaker. After recall of negative and positive words from the centre speaker, the subsequent first recall of words from the side speakers was reduced, regardless of anxiety level of the participant. The emotional interference effect suggests that emotional words interfere with ongoing central processing due to the attentional dwell on the information in auditory working memory.     

Attentional bias towards angry faces is moderated by the activation of a social processing mode in the general population

ABSTRACT

Dot-probe studies usually find an attentional bias towards threatening stimuli only in anxious participants, but not in non-anxious participants. In the present study, we conducted two experiments to investigate whether attentional bias towards angry faces in unselected samples is moderated by the extent to which the current task requires social processing. In Experiment 1, participants performed a dot-probe task involving classification of either socially meaningful targets (schematic faces) or meaningless targets (scrambled schematic faces). Targets were preceded by two photographic face cues, one angry and one neutral. Angry face cues only produced significant cueing scores (i.e. faster target responses if the target replaced the angry face compared to the neutral face) with socially meaningful targets, not with meaningless targets. In Experiment 2, participants classified only meaningful targets, which were either socially meaningful (schematic faces) or not (schematic houses). Again, mean cueing scores were significantly moderated by the social character of the targets. However, cueing scores in this experiment were non-significant in the social target condition and significantly negative in the non-social target condition. These results suggest that attentional bias towards angry faces in the dot-probe task is moderated by the activation of a social processing mode in unselected samples.     

How emotional pictures influence visuospatial binding in short-term memory in ageing and Alzheimer’s disease?

The present study examines the prediction that emotion can facilitate short-term memory. Nevertheless, emotion also recruits attention to process information, thereby disrupting short-term memory when tasks involve high attentional resources. In this way, we aimed to determine whether there is a differential influence of emotional information on short-term memory in ageing and Alzheimer's disease (AD). Fourteen patients with mild AD, 14 healthy older participants (NC), and 14 younger adults (YA) performed two tasks. In the first task, involving visual short-term memory, participants were asked to remember a picture among four different pictures (negative or neutral) following a brief delay. The second task, a binding memory task, required the recognition by participants of a picture according to its spatial location. The attentional cost involved was higher than for the first task. The pattern of results showed that visual memory performance was better for negative stimuli than for neutral ones, irrespective of the group. In contrast, binding memory performance was essentially poorer for the location of negative pictures in the NC group, and for the location of both negative and neutral stimuli in the AD group, in comparison to the YA group. Taken together, these results show that emotion has beneficial effects on visual short-term memory in ageing and AD. In contrast, emotion does not improve their performances in the binding condition.     

Don't look now: Attentional avoidance of emotionally valenced cues

It is often assumed that emotional stimuli receive high priority for processing, and that the distinction between positive and negative valence is fundamental. However, studies of attention to symbolic stimuli, such as words of different valence, have proved inconclusive. In four experiments, control over the emotional attributes of previously neutral line sketches was achieved by associating them with valenced captions. When these newly valenced sketches were paired with neutral stimuli in an attentional search task, they elicited equivalent attentional avoidance. In contrast, in a final experiment, strongly valenced colour pictures captured attention. We suggest that a mechanism acting to limit unnecessary interruptions of ongoing behaviour can inhibit processing of relatively mild emotional stimuli.     

Attentional capture by emotional faces is contingent on attentional control settings

Attentional capture by schematic emotional faces was investigated in two experiments using the flanker task devised by Eriksen and Eriksen (1974). In Experiment 1, participants were presented with a central target (a schematic face that was either positive or negative) flanked by two identical distractors, one on either side (schematic faces that were positive, negative, or neutral). The objective was to identify the central target as quickly as possible. The impact of the flankers depended on their emotional expression. Consistent with a threat advantage hypothesis (negative faces are processed faster and attract more processing resources), responses to positive faces were slower when these were flanked by (response incompatible) negative faces as compared with positive or neutral faces, whereas responses to negative faces were unaffected by the identity of the flankers. Experiment 2 was a standard flanker task with letter stimuli except that the task-neutral flankers were schematic faces that were either positive, negative, or emotionally neutral. In this case, in which faces and emotional expressions were to be ignored, performance seemed entirely unaffected by the faces. This result suggests that attentional capture by emotional faces is contingent on attentional control settings.     

Attentional capture by emotional faces is contingent on attentional control settings

Attentional capture by schematic emotional faces was investigated in two experiments using the flanker task devised by Eriksen and Eriksen (1974). In Experiment 1, participants were presented with a central target (a schematic face that was either positive or negative) flanked by two identical distractors, one on either side (schematic faces that were positive, negative, or neutral). The objective was to identify the central target as quickly as possible. The impact of the flankers depended on their emotional expression. Consistent with a threat advantage hypothesis (negative faces are processed faster and attract more processing resources), responses to positive faces were slower when these were flanked by (response incompatible) negative faces as compared with positive or neutral faces, whereas responses to negative faces were unaffected by the identity of the flankers. Experiment 2 was a standard flanker task with letter stimuli except that the task-neutral flankers were schematic faces that were either positive, negative, or emotionally neutral. In this case, in which faces and emotional expressions were to be ignored, performance seemed entirely unaffected by the faces. This result suggests that attentional capture by emotional faces is contingent on attentional control settings.     

Read-out of emotional information from iconic memory: the longevity of threatening stimuli

Previous research has shown that emotional stimuli are more likely than neutral stimuli to be selected by attention, indicating that the processing of emotional information is prioritized. In this study, we examined whether the emotional significance of stimuli influences visual processing already at the level of transient storage of incoming information in iconic memory, before attentional selection takes place. We used a typical iconic memory task in which the delay of a poststimulus cue, indicating which of several visual stimuli has to be reported, was varied. Performance decreased rapidly with increasing cue delay, reflecting the fast decay of information stored in iconic memory. However, although neutral stimulus information and emotional stimulus information were initially equally likely to enter iconic memory, the subsequent decay of the initially stored information was slowed for threatening stimuli, a result indicating that fear-relevant information has prolonged availability for read-out from iconic memory. This finding provides the first evidence that emotional significance already facilitates stimulus processing at the stage of iconic memory.     

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.     

Who is more prone to distraction? A simple test to evaluate the interference of emotional stimuli in females and males / ¿Quién se distrae más? Un sencillo test para evaluar la interferencia de los estímulos emocionales en mujeres y hombres

Abstract

In order to quantify gender differences in attentional capability depending on the presence of emotional stimuli, the effectiveness of responses to a target stimulus were analysed between groups. Fifty-two men and 52 women carried out two experiments based on the Eriksen flanker task. Half the participants were instructed to indicate the orientation of an arrow without flankers. The other half carried out the same task, but in this case the arrow was flanked by images with sexual or relaxing content. The study suggests that men are faster than women in discriminating the spatial orientation of a relevant stimulus, despite being more prone to distraction by adjacent stimuli. Regarding emotional interference, which is equivalent in both genders, it is higher for images with sexual content compared to those with relaxing content.     

The effect of fearful faces on the attentional blink is task dependent

In a set of three rapid serial visual presentation experiments, we investigated the effect of fearful and neutral face stimuli on the report of trailing scene targets. When the emotional expression of the face stimuli had to be indicated, fearful faces induced a stronger attentional blink (AB) than did neutral faces. However, with identical physical stimulation, the enhancement of the AB by fearful faces disappeared when participants had to judge the faces’ gender. If faces did not have to be reported, no AB was observed. Thus, fearful faces exhibited an effect on the AB that crucially depended on the observer’s attentional set. Hence, the AB can be influenced by an emotional T1 when T1 has to be reported, but this influence is modulated by task context. This result indicates a close connection between temporal attention and emotional processing that is modulated by task context.     

Attentional rubbernecking: Cognitive control and personality in emotion-induced blindness

Emotional stimuli often attract attention, but at what cost to the processing of other stimuli? Given the potential costs, to what degree can people override emotion-based attentional biases? In Experiment 1, participants searched for a single target within a rapid serial visual presentation of pictures; an irrelevant, emotionally negative or neutral picture preceded the target by either two or eight items. At the shorter lag, negative pictures spontaneously induced greater deficits in target processing than neutral pictures did. Thus, attentional biases to emotional information induced a temporary inability to process stimuli that people actively sought. Experiment 2 revealed that participants could reduce this effect through attentional strategy, but that the extent of this reduction was related to their level of the personality traitharm avoidance. Participants lower in harm avoidance were able to reduce emotioninduced blindness under conditions designed to facilitate the ignoring of the emotional stimuli. Those higher in harm avoidance were unable to do so.     

Emotional content enhances true but not false memory for categorized stimuli

Past research has shown that emotion enhances true memory, but that emotion can either increase or decrease false memory. Two theoretical possibilities—the distinctiveness of emotional stimuli and the conceptual relatedness of emotional content—have been implicated as being responsible for influencing both true and false memory for emotional content. In the present study, we sought to identify the mechanisms that underlie these mixed findings by equating the thematic relatedness of the study materials across each type of valence used (negative, positive, or neutral). In three experiments, categorically bound stimuli (e.g., funeral, pets, and office items) were used for this purpose. When the encoding task required the processing of thematic relatedness, a significant true-memory enhancement for emotional content emerged in recognition memory, but no emotional boost to false memory (Exp. 1). This pattern persisted for true memory with a longer retention interval between study and test (24 h), and false recognition was reduced for emotional items (Exp. 2). Finally, better recognition memory for emotional items once again emerged when the encoding task (arousal ratings) required the processing of the emotional aspect of the study items, with no emotional boost to false recognition (Exp. 3). Together, these findings suggest that when emotional and neutral stimuli are equivalently high in thematic relatedness, emotion continues to improve true memory, but it does not override other types of grouping to increase false memory.     

急性应激对工作记忆的影响受工作记忆负荷调节:来自电生理的证据

急性应激如何影响工作记忆还不清楚。采用电影片断诱发被试的急性应激或中性状态后,让其完成数字N-back任务并同时记录脑电。结果发现,低负荷工作记忆诱发的P3显著大于高负荷工作记忆;在0-back任务中,急性应激组诱发的P3显著大于控制组;而在2-back任务中,这种差异不显著。这些结果表明急性应激对工作记忆的影响受工作记忆负荷调节,支持了双竞争理论模型。