Memory for affectively valenced and neutral stimuli in depression: evidence from a novel matching task

Depressed persons have better memory for affectively negative than positive stimuli, a pattern generally not exhibited by non-depressed individuals. The mechanisms underlying this differential memory are not clear. In this study we examined memory for valenced and neutral stimuli in depressed and non-depressed individuals under conditions of relatively unconstrained encoding. We developed a novel task based on the game, Concentration, in which participants tried to match pairs of positive and negative words, and pairs of neutral words, hidden under squares in as few turns as possible. Whereas non-depressed participants selected and turned over positive squares more frequently than they did negative squares, depressed participants selected and turned over positive and negative squares equally often. Depressed participants also matched fewer positive word pairs within the first five minutes of the task than did non-depressed participants, and they exhibited poorer learning of positive words. Depressed and non-depressed participants did not differ in their matching of neutral words. These findings add to a growing literature indicating that depression is characterised by difficulties in the processing of positive stimuli.     

The role of controlled attention on recall in major depression

Information processing biases are hallmark features of major depressive disorder (MDD). Depressed individuals display biased memory and attention for negative material. Given that memory is highly dependent on attention for initial encoding, understanding the interplay of these processes may provide important insight into mechanisms that produce memory biases in depression. In particular, attentional control—the ability to selectively attend to task-relevant information by both inhibiting the processing of irrelevant information and disengaging attention from irrelevant material—may be one area of impairment in MDD. In the current study, clinically depressed (MDD: n = 15) and never depressed (non-MDD: n = 22) participants' line of visual gaze was assessed while participants viewed positive and negative word pairs. For each word pair, participants were instructed to attend to one word (target) and ignore one word (distracter). Free recall of study stimuli was then assessed. Depressed individuals displayed greater recall of negatively valenced target words following the task. Although there were no group differences in attentional control in the context of negative words, attention to negative targets mediated the relationship between depression status and recall of negative words. Results suggest a stronger link between attention and memory for negative material in MDD.     

Deployment of attention in clinical depression during symptom remission

The purpose of the current study was to investigate deployment of attention in clinically depressed patients during the process of symptom remission. Previous research indicates a non-depressed protective bias in attention whereas depressed individuals evidence no bias. A deployment-of-attention task based on negative, positive, and neutral adjectives was administered twice to 15 inpatients with major depression and 15 normal controls, at about 6 weeks apart. From test 1 to test 2, severity of patients' depressive symptoms improved significantly. Acutely depressed patients tended to show an attentional bias towards negative information whereas partially remitted patients manifested no attentional bias. Non-depressed individuals attended less to negative information than (acutely and partially remitted) depressed patients. Non-depressed participants but not depressed patients avoid negative information demonstrating a protective processing bias. Depressed patients are not characterized by a shift towards a pronounced protective pattern during symptom remission.     

阈下抑郁个体对负性情绪刺激的注意解脱困难

本研究拟采用点探测范式及不同情绪内容的面孔刺激（高兴、中性、悲伤和愤怒）考察阈下抑郁个体的负性注意偏向及其内在机制。点探测任务中情绪面孔配对呈现（负性-中性、正性-中性）,配对面孔中的情绪线索位置与靶刺激的位置构成负性一致/不一致和正性一致/不一致条件,同时实验中加入“中性-中性”面孔线索作为一致和不一致条件的对比基线来考察注意偏向的内在机制。结果发现,阈下抑郁个体在负性不一致条件下的反应时显著长于负性一致条件,表明阈下抑郁个体具有对负性刺激的注意偏向;进一步比较发现,阈下抑郁个体在负性不一致条件下的反应时显著的长于“中性-中性”基线条件,而负性一致条件与基线之间差异不显著,表明阈下抑郁个体的负性注意偏向为对负性刺激的注意解脱困难。结果另发现,阈下抑郁个体未能像无抑郁对照组个体表现出对正性刺激的注意偏向。结果表明,处于阈下抑郁状态的个体表现出对负性刺激的注意偏向,具体为对负性刺激的注意解脱困难,其原因可能是由于阈下抑郁个体在注意控制和情绪调节功能上的紊乱。     

外显与内隐记忆的情绪一致性效应

基于Yonelinas等双加工信号检测模型对再认记忆测验中外显记忆与内隐记忆分离的方法,以96名大学生为被试,考察了诱发抑郁与非临床抑郁状态下外显和内隐记忆的情绪一致性效应。结果表明诱发抑郁组和非临床抑郁组对抑郁词的外显记忆成绩显著高于对中性词和愉快词;对抑郁词的内隐记忆成绩亦显著高于对中性词和愉快词,且显著高于控制组对抑郁词的内隐记忆成绩。情绪一致性记忆效应在非临床抑郁个体和诱发抑郁个体的外显和内隐记忆中均存在。     

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.     

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.     

Lack of an Attention Bias Away From Relatively Negative Faces in Dysphoria Is Not Related to Biased Emotion Identification

Eye-tracking-based attention research has consistently shown a lack of a normative attentional bias away from dysphoric face stimuli in depression, characterizing the attention system of non-depressed individuals. However, this more equal attention allocation pattern could also be related to biased emotion identification, namely, an inclination of depressed individuals to attribute negative emotions to non-negative stimuli when processing mood-congruent stimuli. Here, we examined emotion identification as a possible mechanism associated with attention allocation when processing emotional faces in depression. Attention allocation and emotion identification of participants with high (HD; n = 30) and low (LD; n = 30) levels of depression symptoms were assessed using two corresponding tasks previously shown to yield significant findings in depression, using the same face stimuli (sad, happy, and neutral faces) across both tasks. We examined group differences on each task and possible between-task associations. Results showed that while LD participants dwelled longer on relatively positive faces compared with relatively negative faces on the attention allocation task, HD participants showed no such bias, dwelling equally on both. Trait anxiety did not affect these results. No group differences were noted for emotion identification, and no between-task associations emerged. Present results suggest that depression is characterized by a lack of a general attention bias toward relatively positive faces over relatively negative faces, which is not related to a corresponding bias in emotion identification.     

Recollective Experience During Recognition of Emotional Words in Clinical Depression

Earlier work has shown that free recall tasks produce a robust mood-congruent memory effect in depression, whereas recognition tasks produce heterogeneous results. This study aimed to further investigate recognition memory for positive, negative and neutral words in depressed patients and matched comparison participants with the Remember/Know/Guess procedure for assessing recollection and familiarity. No mood-congruent memory bias effect was detected in discrimination abilities. However, depressed patients recollected (more Remember responses) more negative than positive or neutral words, whereas comparison participants recollected more positive than neutral words. No mood-congruent pattern was evidenced for Know responses. However, the depressed patients responded to fewer words overall with Know responses than the comparison participants. These results suggest that the mood-congruent memory pattern in depressed patients is related to conscious recollection rather than to familiarity. Attentional biases toward negative words and elaboration processes and/or encoding in reference to the self may contribute to these findings.     

The effects of suppressing a negative autobiographical memory on concurrent intrusions and subsequent autobiographical recall in dysphoria

Depressed individuals endeavor to suppress intrusive thoughts and memories as a form of mood control. Two predictions from this literature were examined. The 1st was that attempts to suppress a preselected negative memory during a stream-of-consciousness (SOC) task in dysphoric individuals, relative to a no-suppress condition, would lead to relatively speeded access to other negative but not positive memories on a subsequent cue-word recall task. No such effects were predicted for nondysphoric controls. The 2nd prediction was that, across all participants who were asked to suppress memories, higher levels of depressed mood would be associated with more intrusions of the to-be-suppressed memory during the SOC and that this association would be stronger than the comparable relation in participants who were not asked to suppress memories. Results support both predictions.     

Emotion context insensitivity in major depressive disorder

The present study tested 3 competing views of how depression alters emotional reactivity: positive attenuation (reduced positive), negative potentiation (increased negative), and emotion context insensitivity (ECI; reduced positive and negative). Normative and idiographic stimuli that elicited happy, sad, and neutral states were presented to currently depressed, formerly depressed, and healthy control individuals while experiential, behavioral, and autonomic responses were measured. Currently depressed individuals reported less sadness reactivity and less happiness experience across all conditions than did the other participants, and they exhibited a more dysphoric response to idiographic than to normative stimuli. Overall, data provide partial support for the positive attenuation and ECI views. Depression may produce mood-state-dependent changes in emotional reactivity that are most pronounced in emotion experience reports.     

Positive effects of subclinical depression in prospective memory and ongoing tasks in young and old adults

Results reported in the literature show that depression can have either negative or neutral effects on prospective memory (PM). The goal of the present study was to broaden the analysis of depression-related effects on PM, with regard to the possibility that subclinical depression may have positive influence on PM. A total of 120 participants from four groups (young/old, subclinically depressed/non-depressed) completed event- and time-based PM tasks embedded in the linear orders task or stories task, respectively. In the event-based PM task no effects of depression were found, whereas depressed participants were more accurate in the time-based PM task, where higher monitoring during the last minute of the task was observed. It was also found that depressed participants built a mental model in the linear orders task more accurately than controls. Results of the present study are discussed with reference to the analytical rumination hypothesis.     

Training the removal of negative information from working memory: A preliminary investigation of a working memory bias modification task

Rumination in depressed adults is associated with a bias toward retaining negative information in working memory. We developed a task designed to modify this cognitive bias by having subjects repeatedly practice removing negative words from working memory, thereby enabling them to retain positive and neutral words. To assess the efficacy of this task, we recruited 60 adults who reported elevated repetitive negative thought (RNT) and randomly assigned them to receive a single administration of either the working memory bias modification (WMBM) task or a control task. Subjects in the WMBM condition exhibited greater reduction in proactive interference for negative information than did those in the control condition. These results suggest that the WMBM task reduces biased retention of negative information in working memory and, thus, may be useful in investigating the possible causal role of this cognitive bias in RNT or depression.     

Divided attention enhances the recognition of emotional stimuli: evidence from the attentional boost effect

The present study examined predictions of the early-phase-elevated-attention hypothesis of the attentional boost effect (ABE), which suggests that transient increases in attention at encoding, as instantiated in the ABE paradigm, should enhance the recognition of neutral and positive items (whose encoding is mostly based on controlled processes), while having small or null effects on the recognition of negative items (whose encoding is primarily based on automatic processes). Participants were presented a sequence of negative, neutral and positive stimuli (pictures in Experiment 1, words in Experiment 2) associated to target (red) squares, distractor (green) squares or no squares (baseline condition). They were told to attend to the pictures/words and simultaneously press the spacebar of the computer when a red square appeared. In a later recognition task, stimuli associated to target squares were recognised better than stimuli associated to distractor squares, replicating the standard ABE. More importantly, we also found that: (a) the memory enhancement following target detection occurred with all types of stimuli (neutral, negative and positive) and (b) the advantage of negative stimuli over neutral stimuli was intact in the DA condition. These findings suggest that the encoding of negative stimuli depends on both controlled (attention-dependent) and automatic (attention-independent) processes.     

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.     

On Lions and Adolescents: Affective Temperaments and the Influence of Negative Stimuli on Memory

The present study investigated the relation between reaction to negative stimuli and memory for stimuli. The relation was further investigated using as a framework individuals’ affective temperaments (AFTs). Eighty adolescents participated in the study. The AFTs are based on selfreported affect and categorizes individuals in four temperaments: self-actualizing, high affective, low affective and self-destructive. Reaction to negative stimuli was measured by interpretation of specific words in a short story. Two days later, participants were presented with a list of words and asked which of them were present in the short story. Individuals’ AFTs were expected to predict the promotion of pleasure or the prevention of displeasure. On a general level, reaction to negative stimuli predicted memory for negative, positive and neutral words. At an individual level, self-actualizers and high affectives’ negative reaction predicted the memory of positive words (i.e., promotion). In contrast, low affectives’ negative and positive reaction predicted the memory of neutral words (i.e., prevention).     

情绪一致性对有意遗忘的影响

有意遗忘是强调遗忘的有意性和指向性。对负性情绪的有意遗忘有利于个体的身心健康。本研究采用单字范式,实验一以正性、负性和中性情绪词为材料,探讨了情绪材料对有意遗忘的影响。结果发现,三类词语均表现出了显著的有意遗忘效应;实验二在实验一的基础上加入了情绪状态,探讨了情绪状态和情绪材料对有意遗忘的影响,结果发现,在积极情绪状态下,被试更多地遗忘负性情绪词;在消极情绪状态下,被试更多地遗忘中性词。表明个体对情绪信息的有意遗忘既受信息的情绪性影响,又受个体情绪状态的影响。     

Emotional enhancement of immediate memory: Positive pictorial stimuli are better recognized than neutral or negative pictorial stimuli

We examined emotional memory enhancement (EEM) for negative and positive pictures while manipulating encoding and retrieval conditions. Two groups of 40 participants took part in this study. Both groups performed immediate implicit (categorization task) and explicit (recognition task) retrieval, but for one group the tasks were preceded by incidental encoding and for the other group by intentional encoding. As indicated by the sensitivity index (d'), after incidental encoding positive stimuli were easier to recognize than negative and neutral stimuli. Participants' response criterion was more liberal for negative stimuli than for both positive and neutral ones, independent of encoding condition. In the implicit retrieval task, participants were slower in categorizing positive than negative and neutral stimuli. However, the priming effect was larger for emotional than for neutral stimuli. These results are discussed in the context of the idea that the effect of emotion on immediate memory enhancement may depend on the intentionality to encode and retrieve information.     

情绪评价任务中抑郁个体的分心抑制机制实验研究

本实验使用情绪负启动技术,在情绪评价任务中考察了抑郁个体和正常被试对正、负情绪词分心抑制方面的差异。结果显示,与控制条件下相比,非抑郁控制组被试在负启动条件下对探测显示中正、负性靶子词的反应时间更长;抑郁个体只表现在对探测显示中正性靶子词反应时的延长,负性靶子词未出现负启动效应。结果说明,抑郁个体对负性信息存在抑制机制障碍,对负性信息的偏向与选择性注意中的维持成分有关。这提示心理治疗家应该注重训练抑郁个体对负性信息的抑制能力,预防抑郁复发的目标应集中在注意持续的控制上。