Effect of negative emotional content on attentional maintenance in working memory

ABSTRACT

Previous research has shown that emotional stimuli may interfere with working memory (WM) processes, but little is known about the process affected. Using a complex span task, the present study investigated the influence of processing negative emotional content on attentional maintenance in WM. In two experiments conducted under articulatory suppression, participants were asked to remember a series of five letters, each of which was followed by an image to be categorised. In half of the trials, the images were negative and in the other half, they were neutral. In both experiments, our results showed longer processing times for emotional stimuli than neutral stimuli, and lower memory performance when participants processed negative stimuli. We propose that emotional stimuli direct more attentional resources towards the processing component of the WM task, thereby reducing the storage capacity available for the items that are to be remembered.     

Sticky thoughts: depression and rumination are associated with difficulties manipulating emotional material in working memory

Cognitive inflexibility may play an important role in rumination, a risk factor for the onset and maintenance of depressive episodes. In the study reported here, we assessed participants' ability to either reverse or maintain in working memory the order of three emotion or three neutral words. Differences (or sorting costs) between response latencies in backward trials, on which participants were asked to reverse the order of the words, and forward trials, on which participants were asked to remember the words in the order in which they were presented, were calculated. Compared with control participants, depressed participants had higher sorting costs, particularly when presented with negative words. It is important to note that rumination predicted sorting costs for negative words but not for positive or neutral words in the depressed group. These findings indicate that depression and rumination are associated with deficits in cognitive control.     

Effects of emotional content on working memory capacity

Emotional events tend to be remembered better than neutral events, but emotional states and stimuli may also interfere with cognitive processes that underlie memory performance. The current study investigated the effects of emotional content on working memory capacity (WMC), which involves both short term storage and executive attention control. We tested competing hypotheses in a preregistered experiment (N?=?297). The emotional enhancement hypothesis predicts that emotional stimuli attract attention and additional processing resources relative to neutral stimuli, thereby making it easier to encode and store emotional information in WMC. The emotional impairment hypothesis, by contrast, predicts that emotional stimuli interfere with attention control and the active maintenance of information in working memory. Participants completed a common measure of WMC (the operation span task; Turner, M. L., &; Engle, R. W. [1989]. Is working memory capacity task dependent? Journal of Memory and Language, 28, 127–154) that included either emotional or neutral words. Results revealed that WMC was reduced for emotional words relative to neutral words, consistent with the emotional impairment hypothesis.     

Working memory capacity and spontaneous emotion regulation in generalised anxiety disorder

Researchers have postulated that deficits in cognitive control are associated with, and thus may underlie, the perseverative thinking that characterises generalised anxiety disorder (GAD). We examined associations between cognitive control and levels of spontaneous state rumination following a stressor in a sample of healthy control participants (CTL; n?=?27) and participants with GAD (n?=?21). We assessed cognitive control by measuring working memory capacity (WMC), defined as the ability to maintain task-relevant information by ignoring task-irrelevant information. To this end, we used an affective version of the reading span task with valenced (negative or neutral) distractors. Lower WMC in the presence of negative distractors was associated with greater state rumination in the GAD group, but not in the CTL group. These findings suggest that difficulty maintaining task-relevant information due to interference from negative distractors contributes to perseverative thinking in GAD.     

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.     

Threat-relevance impairs executive functions: negative impact on working memory and response inhibition

The effects of emotional stimulus content on attention are well-known. In contrast, the impact of emotional information on higher executive control functions is undetermined. To elucidate the role of negative emotion in cognitive control, 56 adult female participants performed a combined working memory and response inhibition task, with threat-relevant (spider and snake) and neutral (flower and mushroom) stimuli. Threat-relevant stimuli impaired performance, by causing prolonged response times to working memory items and increased response inhibition error rate relative to neutral stimuli. The impaired response inhibition was only evident when threat-relevant stimuli co-occurred with working memory matches, in line with a common resource pool view of executive functions and emotion processing. Individual differences in reported fear of spiders were associated with differences of inhibitory control, while fear of snakes was associated with impaired overall accuracy on working memory trials. The results are discussed in relation to the dual-competition framework for interaction between executive functions and emotion (Pessoa, 2009).     

Emotion processing facilitates working memory performance

The effect of emotional stimulus content on working memory performance has been investigated with conflicting results, as both emotion-dependent facilitation and impairments are reported in the literature. To clarify this issue, 52 adult participants performed a modified visual 2-back task with highly arousing positive stimuli (sexual scenes), highly arousing negative stimuli (violent death) and low-arousal neutral stimuli. Emotional stimulus processing was found to facilitate task performance relative to that of neutral stimuli, both in regards to response accuracy and reaction times. No emotion-dependent differences in false-alarm rates were found. These results indicate that emotional information can have a facilitating effect on working memory maintenance and processing of information.     

Emotion processing facilitates working memory performance

The effect of emotional stimulus content on working memory performance has been investigated with conflicting results, as both emotion-dependent facilitation and impairments are reported in the literature. To clarify this issue, 52 adult participants performed a modified visual 2-back task with highly arousing positive stimuli (sexual scenes), highly arousing negative stimuli (violent death) and low-arousal neutral stimuli. Emotional stimulus processing was found to facilitate task performance relative to that of neutral stimuli, both in regards to response accuracy and reaction times. No emotion-dependent differences in false-alarm rates were found. These results indicate that emotional information can have a facilitating effect on working memory maintenance and processing of information.     

Working memory load reduces the late positive potential and this effect is attenuated with increasing anxiety

Emotion regulation decreases the processing of arousing stimuli, as indexed by the late positive potential (LPP), an electrocortical component that varies in amplitude with emotional arousal. Emotion regulation increases activity in the prefrontal areas associated with cognitive control, including the dosolateral prefrontal cortex (DLPFC). The present study manipulated working memory load, known to activate the DLPFC, and recorded the LPP elicited by aversive and neutral IAPS pictures presented during the retention interval. The LPP was larger on low-load compared to high-load trials, and on trials with aversive compared to neutral pictures. These LPP data suggest that emotional content and working memory load have opposing effects on attention to distracting stimuli. State anxiety was associated with reduced modulation of the LPP by working memory load. Results are discussed in terms of competition for attention between emotion and cognition and suggest a relationship between DLPFC activation and the allocation of attentional resources to distracting visual stimuli–a relationship that may be disrupted with increasing anxiety.     

Emotion processing effects on interference resolution in working memory

The interaction between emotion and working memory maintenance, load, and performance has been investigated with mixed results. The effect of emotion on specific executive processes such as interference resolution, however, remains relatively unexplored. In this series of studies, we examine how emotion affects interference resolution processes within working memory by modifying the Recency-probes paradigm (Monsel, 1978) to include emotional and neutral stimuli. Reaction time differences were compared between interference and non-interference trials for neutral and emotional words (Studies 1 & 3) and pictures (Study 2). Our results indicate that trials using emotional stimuli show a relative decrease in interference compared with trials using neutral stimuli, suggesting facilitation of interference resolution in the former. Furthermore, both valence and arousal seem to interact to produce this facilitation effect. These findings suggest that emotion facilitates response selection amid interference in working memory.     

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.     

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.     

The effects of optimism and pessimism on updating emotional information in working memory

In the present study we elucidate the emotional and executive control interactions that might underlie optimism and pessimism. Participants completed a self-report measure of optimism/pessimism and performed an emotion faces categorisation task and an emotion n-back task in which they indicated whether each of a series of faces had the same or a different emotional expression (happy, sad, neutral) as the face presented two trials before. Trials were structured to measure latency to update emotional content in working memory (WM). More pessimistic individuals formed connections among positive stimuli, and broke connections among positive and sad stimuli, in WM more slowly than did less pessimistic individuals; levels of optimism/pessimism did not affect the rate with which individuals formed and broke connections among neutral representations in WM. It appears, therefore, that levels of pessimism are related to specific affective cognitive mechanisms in WM that may be involved in emotion regulation.     

How age affects memory task performance in clinically normal hearing persons

The main objective of this study is to investigate memory task performance in different age groups, irrespective of hearing status. Data are collected on a short-term memory task (WAIS-III Digit Span forward) and two working memory tasks (WAIS-III Digit Span backward and the Reading Span Test). The tasks are administered to young (20–30 years, n = 56), middle-aged (50–60 years, n = 47), and older participants (70–80 years, n = 16) with normal hearing thresholds. All participants have passed a cognitive screening task (Montreal Cognitive Assessment (MoCA)). Young participants perform significantly better than middle-aged participants, while middle-aged and older participants perform similarly on the three memory tasks. Our data show that older clinically normal hearing persons perform equally well on the memory tasks as middle-aged persons. However, even under optimal conditions of preserved sensory processing, changes in memory performance occur. Based on our data, these changes set in before middle age.     

Role of working memory load on selective attention to affectively valent information

Empirical evidence obtained with neutral stimuli has shown that selective attention relies on working memory functions as distractor processing occurs under conditions of high but not of low working memory load. We investigated whether these findings also hold for affectively valent distractors. In three experiments, participants completed the original Flanker task with famous people (Exps 1 and 2) and an affective Flanker task (Exp. 3) in which positive and negative words were presented superimposed onto happy, angry, and neutral faces under conditions of high or low working memory load. In line with past findings, results showed greater interference effects due to processing of distractors showing known people under high working memory load. In contrast interference effects due to processing of valent distractors occurred regardless of working memory load. The present findings are in contrast with those reported with neutral stimuli as they indicate that automatic evaluation of incoming affectively valent information occurs regardless of task priorities and of working memory load.     

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.     

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.     

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.     

Working memory load moderates late attentional bias in social anxiety

The vigilance–avoidance hypothesis suggests that socially anxious individuals attempt to detect signs that they are being evaluated (vigilance) and subsequently direct attention away from such stimuli (avoidance). Although extensive evidence supports vigilance, data concerning subsequent avoidance is equivocal. Drawing from models of attention, the current study hypothesised that working memory load moderates late attentional bias in social anxiety such that avoidance occurs if working memory load is low, and difficulty disengaging attention occurs if working memory load is high. Forty-one undergraduates (19 socially anxious; 22 non-anxious controls) completed a dot-probe task with emotional (happy and disgust) and neutral facial expressions and a concurrent n-back task. Results supported the hypothesis such that socially anxious subjects demonstrated avoidance of disgust faces when working memory load was absent, but had difficulty disengaging attention during high working memory load. Theoretical implications and directions for future research are discussed.