情绪性记忆的主动遗忘

情绪性记忆的主动遗忘, 是指人们有意识地主动地遗忘带有情绪色彩的记忆内容, 但更多的是那些带来痛苦的负性情绪性记忆。主动遗忘又分为定向遗忘和压抑遗忘, 项目法和字表法是实验室中研究定向遗忘的主要方法, 而白熊任务和TNT任务是研究压抑遗忘的主要范式, 研究者们围绕两种遗忘做了大量研究。未来的研究应更关注情绪性记忆遗忘的不同心理机制, 不同研究范式与心理机制的交互作用, 情绪性记忆遗忘的个体差异, 情绪性记忆遗忘中事件遗忘和情绪反应遗忘的分离等 问题。     

跨视听通道主动遗忘的期待加工与抑制控制过程：来自ERPs的证据

基于视觉通道的研究表明,人们可以通过主动抑制记忆提取而实现遗忘。但目前对跨通道的主动遗忘尚缺乏探讨。本研究以声音为记忆线索,以文字为目标记忆,采用“想/不想”范式,探究主动遗忘在跨视听通道条件下的可行性。结果发现,“不想”条件下目标记忆的回忆率低于基线条件,主动遗忘发生。此外,我们通过分离任务指令和记忆线索的呈现时间,在中央区域的ERP中发现了记忆抑制的期待效应;并在额叶观察到“不想”条件下晚期正成分的增强,反映了持续的抑制控制过程。本研究不但验证了跨视听通道主动遗忘的可能性,而且第一次从ERPs角度分离了跨通道遗忘相关的期待加工和抑制控制过程。     

负性情绪词语在外显和内隐记忆测验中的定向遗忘效应

以两类具有不同负性情绪强度值的高频汉语双字词为材料,采用项目法定向遗忘范式,探究负性情绪词语在外显和内隐记忆测验中是否存在定向遗忘效应。结果显示,(1)在外显记忆测验中,强、弱负性词均出现了显著的定向遗忘并且弱负性词的定向遗忘效应大于强负性词;(2)在内隐记忆测验中,只有弱负性词出现了显著的定向遗忘,而强负性词则无。可见,内隐记忆测验中的定向遗忘效应对负性信息比外显记忆测验更加敏感。     

自我参照对情绪性记忆定向遗忘的影响

关于自我参照效应的研究大多从信息编码角度考察自我参照的加工优势, 但作为记忆过程的另一重要方面, 自我参照对遗忘影响的研究较少。遗忘自身经历的情绪性记忆是日常生活中的常见现象。研究采用项目法定向遗忘范式(item-method directed forgetting)考察了自我参照对情绪性记忆定向遗忘的影响。实验一和实验二的结果都表明参照方式会影响定向遗忘：自我参照条件下的材料会发生定向遗忘; 而他人参照条件下的材料不会发生定向遗忘, 两种参照方式下材料间区辨性的不同是导致这一现象的原因。此外, 实验二采用回忆测试发现：自我参照对不同效价的情绪性记忆定向遗忘产生了不同影响, 而自我提升(self-enhancement)动机在其中起着重要的调节作用。     

负性情绪材料的定向遗忘及心理机制

采用项目法定向遗忘的研究范式,在两个实验中分别采用文字和图片材料考察了情绪性记忆定向遗忘的效果及其心理机制。实验中采用了中性和负性两种实验材料,设置了两种记忆指令出现时间（2秒后提示和5秒后提示）,相对于中性材料,被试更不容易忘记负性材料。记忆指令出现的时间只影响图片材料的定向遗忘。研究表明负性情绪会干扰定向遗忘,选择性编码理论可以解释情绪性文字材料的定向遗忘,而抑制理论更能解释情绪性图片材料的定向遗忘效应。     

复述、提取抑制与有意遗忘的实验研究

有意遗忘是关于记忆研究的另一种实验范式,对于在实验中出现的要求遗忘的学习项目的记忆成绩差于要求记忆的项目的结果,目前主人存在着两种理论解释：基于编码的理论和基于提取抑制的理论。该实验运用单字提示方式,采用控制较为严密的补笔测验方法和加入所谓的“无关项”,对有意遗忘的心理过程进行进一步的探讨,实验表明：在单了提示方式下,被试在进行有意遗忘的过程中,既对记忆项进行了有意的复述又对遗忘项产生了提取抑制。     

情绪对连续事件定向遗忘的影响

本研究采用项目法定向遗忘范式以中性和负性连续事件的视频为实验材料, 通过2个实验考察了情绪对连续事件定向遗忘的影响, 并进一步探讨了情绪对细节记忆和要义记忆的定向遗忘的影响。结果发现, 情绪可以消除细节记忆的定向遗忘效应, 而仅有要义记忆的定向遗忘效应则主要受到事件连续性而非情绪的影响。     

情绪对提取诱发遗忘的影响

从学习材料的情绪性和提取过程的情绪状态两方面考察了情绪对提取诱发遗忘的影响。结果发现提取练习对情绪性与非情绪性材料引发了同等程度的遗忘;提取练习阶段,当被试处于正性或中性情绪状态下也会发生明显的提取诱发遗忘现象,而当被试处于负性情绪状态时,提取练习不会导致对未提取项目的遗忘。研究结果表明,学习材料的情绪性不影响提取诱发遗忘,而提取过程的情绪状态会对提取诱发遗忘产生影响,负性情绪状态可以消除提取诱发遗忘。     

单字法有意遗忘的内部心理机制：基于多项式加工树模型的分析

通过构建使用单个双字词作为实验材料,并在测验阶段全面考察记忆提取过程的MPT模型,考察单字法有意遗忘的心理机制。结果发现,对于TBF/R项目,遗忘组的储存能力和提取能力均弱于记忆组;对于TBR/R项目,遗忘组的储存能力强于记忆组。并且无论对于短时SOA还是长时SOA,遗忘组对TBF项目后探测刺激的反应时都显著长于TBR项目。研究表明,单字法有意遗忘现象是由选择性复述、注意抑制和提取抑制三种机制共同作用的结果。     

提取诱发遗忘：项目强度与测试顺序的影响

提取诱发遗忘是指对先前学过的部分材料进行提取练习会使与练习材料相关的其它材料发生遗忘。目前该现象存在抑制与非抑制理论之争。本研究以64名大学生为被试,通过考察项目强度和测试顺序对提取诱发遗忘的影响,对上述争论进行了探讨。结果表明：（1）只有高强度项目才会引发提取诱发遗忘;（2）当控制由测试顺序所产生的输出干扰效应后,高强度项目仍然会引发提取诱发遗忘。本研究结果支持了提取诱发遗忘的抑制理论。     

记忆抑制在正常人群与抑郁人群中的研究进展

抑郁症认知障碍的突出表现之一为患者的负性记忆偏向。已有研究常关注患者对负性信息自下而上的选择性注意,往往忽略了自上而下执行控制障碍对记忆的影响。近年研究提示,抑郁症患者和抑郁状态个体的记忆抑制缺陷在其负性记忆偏向的形成和维持中起到了重要作用,无法有效地主动抑制负性记忆可能是患者持续性负性反刍的主要原因。从抑郁症自上而下的执行控制缺陷入手,研究患者的记忆抑制障碍与其主要症状－负性反刍间的相关性,不仅能从理论上丰富Beck的抑郁症认知模型,还能指导临床建立更准确的预后评估指标,同时制定更有效的治疗方案。本文分别介绍了健康成人及抑郁症患者和抑郁状态个体的记忆抑制研究现状,并就当前在抑郁人群研究领域亟待解决的三个问题进行了探讨。     

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。     

Cognitive and neural consequences of memory suppression in major depressive disorder

Negative biases in cognition have been documented consistently in major depressive disorder (MDD), including difficulties in the ability to control the processing of negative material. Although negative information-processing biases have been studied using both behavioral and neuroimaging paradigms, relatively little research has been conducted examining the difficulties of depressed persons with inhibiting the retrieval of negative information from long-term memory. In this study, we used the think/no-think paradigm and functional magnetic resonance imaging to assess the cognitive and neural consequences of memory suppression in individuals diagnosed with depression and in healthy controls. The participants showed typical behavioral forgetting effects, but contrary to our hypotheses, there were no differences between the depressed and nondepressed participants or between neutral and negative memories. Relative to controls, depressed individuals exhibited greater activity in right middle frontal gyrus during memory suppression, regardless of the valence of the suppressed stimuli, and differential activity in the amygdala and hippocampus during memory suppression involving negatively valenced stimuli. These findings indicate that depressed individuals are characterized by neural anomalies during the suppression of long-term memories, increasing our understanding of the brain bases of negative cognitive biases in MDD.     

Emotional and non-emotional memories are suppressible under direct suppression instructions

Research on retrieval suppression has produced varying results concerning whether negatively valenced memories are more or less suppressible than neutral memories. This variability may arise if, across studies, participants adopt different approaches to memory control. Cognitive and neurobiological research points to two mechanisms that achieve retrieval suppression: thought-substitution and direct suppression (Benoit & Anderson, 2012; Bergström, de Fockert, & Richardson-Klavehn, 2009). Using the Think/No-think paradigm, this study examined whether participants can inhibit neutral and negatively valenced memories, using a uniform direct suppression strategy. Importantly, when strategy was controlled, negative and neutral items were comparably inhibited. Participants reported high compliance with direct suppression instructions, and success at controlling awareness predicted forgetting. These findings provide the first evidence that direct suppression can impair negatively valenced events, and suggest that variability in forgetting negative memories in prior studies is unlikely to arise from difficulty using direct suppression to control emotionally negative experiences.     

Suppressing Unwanted Memories

ABSTRACT— When reminded of something we would prefer not to think about, we often try to exclude the unwanted memory from awareness. Recent research indicates that people control unwanted memories by stopping memory retrieval, using mechanisms similar to those used to stop reflexive motor responses. Controlling unwanted memories is implemented by the lateral prefrontal cortex, which acts to reduce activity in the hippocampus, thereby impairing retention of those memories. Individual differences in the efficacy of these systems may underlie variation in how well people control intrusive memories and adapt in the aftermath of trauma. This research supports the existence of an active forgetting process and establishes a neurocognitive model for inquiry into motivated forgetting.     

Neural processing associated with true and false memory retrieval

We investigated the neural bases for false memory with fMRI by examining neural activity during retrieval processes that yielded true or false memories. We used a reality monitoring paradigm in which participants saw or imagined pictures of concrete objects. (A subsequent misinformation task was also used to increase false memory rates.) At test, fMRI data were collected as the participants determined whether they had seen or had only imagined the object at study. True memories were of seen pictures accurately endorsed as seen, and for false memories were of imagined pictures falsely endorsed as seen. Three distinct patterns of activity were observed: Left frontal and parietal activity was not different for true and for false memories, whereas activity was greater for true than for false memories in occipital visual regions and posterior portions of the parahippocampal gyrus, and activity was greater for false than for true memories in right anterior cingulate gyrus. Possible interpretations are discussed.     

抑制引起的遗忘及其神经机制

当面对不愉快的提醒时, 人们通常会试图阻止那些不想要的记忆出现在脑海中。先前的研究表明, 抑制不想要的记忆的检索会降低这些记忆的可及性, 引起遗忘, 这一效应称为抑制引起的遗忘(suppression- induced forgetting, SIF)。SIF的神经机制涉及右背外侧前额叶皮层和额中回的激活增加, 以及海马的激活受到抑制。SIF的程度受记忆材料的情绪效价、个体的病理性情绪状态和训练的影响。未来研究应在深入了解SIF神经机制的基础上, 考虑如何提高临床病理性记忆的SIF效果, 以达到治疗目的。     

FUNCTIONAL MAGNETIC RESONANCE IMAGING OF SEMANTIC MEMORY PROCESSES IN THE FRONTAL LOBES

Abstract— Frontal-lobe activation during semantic memory performance was examined using functional magnetic resonance imaging (fMRI), a noninvasive technique for localizing neural activity associated with cognitive function. Left inferior prefrontal cortex was more activated for semantic than for perceptual encoding of words, and for initial than for repeated semantic encoding of words. Decreased activation for semantic encoding of repeated words reflects repetition priming, that is, implicit retrieval of memory gained in the initial semantic encoding of a word. The left inferior prefrontal region may sub-serve semantic working memory processes that participate in semantic encoding and that have decreased demands when such encoding can be facilitated by recent semantic experience. These results demonstrate that fMRI can visualize changes in an individual's brain function associated with the encoding and retrieval of new memories.     

记忆提取研究的新进展

该文从3个方面回顾了记忆提取研究领域内的最新进展:(1)记忆编码和提取之间的关系,主要针对提取过程的自动性和控制性及相应的神经机制进行了讨论;(2)基于记忆提取的抑制机制,主要涉及指向性遗忘、提取-练习范式的研究及负启动范式在记忆提取研究中的应用;(3)工作记忆能力与记忆提取之间的关系,主要集中于工作记忆能力与控制性记忆提取及记忆提取中的抑制机制之间的关系。