有意遗忘的脑机制

有意遗忘是指个体主动忘记无用和过时的信息,本质是记忆的主动抑制,包括定向遗忘和压抑遗忘。在定向遗忘中,记忆抑制既发生在编码阶段也发生在提取阶段,脑机制研究支持编码抑制理论和提取抑制理论;在压抑遗忘中,think和No-think所激活的脑区不同,No-think引起前额区域的激活增强和海马的激活减弱。未来应开展定向遗忘和压抑遗忘的脑机制差异研究,注重记忆抑制和其他心理活动抑制之间的差异研究,关注创伤个体的有意遗忘研究,拓展记忆控制神经网络的可塑性研究。     

Emotional constraints on intentional forgetting

One way people control the contents of their minds is intentional forgetting—voluntarily forgetting events after they have happened. The events people would most like to forget are unpleasant and emotional. This study used a directed forgetting procedure with emotional and neutral pictures to examine whether people can intentionally forget emotional events as easily as mundane ones. When the to-be-forgotten list was neutral, participants showed successful intentional forgetting. But when the to-be-forgotten list was emotional, directed forgetting failed. Results contribute to understanding the ways that emotion constrains mental control by capturing mental processes including memory retrieval. Emotion may short-circuit attempts to forget those parts of the past people would most like to forget.     

Impaired directed forgetting in abstinent heroin addicts

Drug-related memories persist long into abstinence and are potent elicitors of drug craving and relapse. We report two experiments examining whether heroin-dependent individuals are impaired in intentionally suppressing drug-related memories. Experiment 1 adopted the Item paradigm where addicts and healthy controls were presented with a list of words each followed by a remember or forget cue. Experiment 2 adopted the List paradigm where they studied one list of items and were then split into a remember group and a forget group. Both groups studied a second list, except that the forget group was told to forget the first list. Compared with controls, addicts showed a reduced directed forgetting effect in the Item method and a total absence of one measure of directed forgetting in the List method (List 2 benefits). Results indicate that heroin addicts are impaired in directed forgetting and that the deficits are likely associated with memory encoding as opposed to retrieval. Possible problems include reduced ability in actively suppressing/stopping encoding of irrelevant information into memory or inability in changing/resetting encoding strategies. In neither experiment did the addicts show any differential directed forgetting effects between drug-related words and neutral words, indicating the generic nature of their intentional forgetting deficits.     

The role of intentional forgetting in reducing children's retroactive interference.

Preschool and kindergarten children's retention of stories was examined in the presence of interfering information and instructions to forget. Children learned 2 stories and, 24 hr later, were asked to recall the 1st or 2nd story learned. Some of the children were instructed, either following acquisition or just prior to the retention test, to forget the 2nd, or interfering, story. A model was used to isolate storage and retrieval effects, and the results showed that (a) retroactive interference affected both storage- and retrieval-based forgetting rates for the younger children but only storage-based forgetting rates for the older children, (b) intentional forgetting reduced retroactive interference primarily by attenuating storage-based forgetting regardless of age, (c) intentional forgetting instructions were effective only at acquisition for preschoolers but at both acquisition and retention for kindergarteners, and (d) all children recalled the to-be-forgotten story as well as they recalled the to-be-remembered story. These results are interpreted in terms of reorganization and distinctiveness effects in storage.     

高低创造性思维水平者定向遗忘效应的差异研究

采用单字法定向遗忘范式,考察远距离联想任务得分高低者在中性和负性词语定向遗忘效应上的差异,来探讨创造性思维水平高低与主动抑制的关系。实验采用2(高/低创造性思维水平)×2(中性/负性词汇)×2(记住/忘记指令)×2(2s/5s时间间隔)混合设计,发现高低创造力组,在材料不同呈现时间下,对不同情绪材料的定向遗忘效应分别不同。低创者在2s和5s以及高创者在5s时间间隔时,均对中性词语表现出定向遗忘效应,而对负性词汇没有表现出明显的定性遗忘效应。高创者在2s时间间隔下,对中性和负性词语均表现出定向遗忘效应。结果表明较短时间内高创者对负性情绪的主动抑制能力优于低创者。     

Retrieval practice can eliminate list method directed forgetting

It has recently been shown that retrieval practice can reduce memories’ susceptibility to interference, like retroactive and proactive interference. In this study, we therefore examined whether retrieval practice can also reduce list method directed forgetting, a form of intentional forgetting that presupposes interference. In each of two experiments, subjects successively studied two lists of items. After studying each single list, subjects restudied the list items to enhance learning, or they were asked to recall the items. Following restudy or retrieval practice of list 1 items, subjects were cued to either forget the list or remember it for an upcoming final test. Experiment 1 employed a free-recall and Experiment 1 a cued-recall procedure on the final memory test. In both experiments, directed forgetting was present in the restudy condition but was absent in the retrieval-practice condition, indicating that retrieval practice can reduce or even eliminate this form of forgetting. The results are consistent with the view that retrieval practice enhances list segregation processes. Such processes may reduce interference between lists and thus reduce directed forgetting.     

定向遗忘的编码加工机制

有目的的遗忘(定向遗忘)需要耗费认知努力吗?有研究发现, 定向遗忘可能是被动衰减的结果, 即F项目(需要遗忘的项目)未获得有效复述是选择性复述了R项目(需要记住的项目)造成的, 这一加工过程不需要认知努力; 但也有研究表明, 定向遗忘过程可能是遗忘线索诱发的对记忆加工的主动抑制, 需要耗费认知努力, 脑认知研究中发现的前额叶ERPs成分为这一机制提供了证据。还有一种观点认为, 定向遗忘编码过程可能同时包含主动抑制与被动衰减, 但是尚不清楚两种加工机制相互作用的方式。为进一步澄清定向遗忘编码阶段的认知机制, 未来研究需要将非认知因素纳入考察, 并关注不同人群的定向遗忘特征, 在此基础上尝试解决理论争议。     

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。     

越努力去忘就越能忘记吗？—情绪材料定向遗忘的"剂量效应"

采用项目法定向遗忘研究范式,在两个实验中分别使用情绪性语词和图片材料,考察主观努力程度影响情绪材料定向遗忘的心理机制。研究采用2(语词或图片情绪效价：正词/负词)×2（指示符：记住/忘记)×3（努力程度：20%/60%/100%）的被试内设计,因变量为情绪性语词或图片的再认率和定向遗忘效应。结果表明,正效价词在三种努力程度忘记条件的再认率无差别,而越努力去忘记负效价词,反而越能记住;正负效价的图片材料都呈现出越努力去忘记反而越能记住的特点。以上结果表明,语词与图片分别适合有意识加工和无意识加工,记住指令导致对情绪性语词和图片的选择性复述,符合选择性复述/被动衰退理论,而不同努力程度的忘记指令又引发了对情绪性语词和图片的主动抑制,符合注意抑制/执行控制理论。     

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。     

Wiping out memories: New support for a mental context change account of directed forgetting

Costs and benefits of directed forgetting are observed when a between-list instruction to forget List 1 impairs List 1 recall while enhancing List 2 recall. These effects are often ascribed to intentional inhibition of List 1. Contrary to this inhibition account, we found that a forget instruction did not produce costs unless an explicit instruction to concentrate on List 2 was used (Experiment 1). Alternatively, costs may be ascribed to a shift in mental context between encoding and retrieval. Consistent with this mental context-change account, an unexpected task (wiping the computer screen and one's hands) produced costs comparable to a forget instruction, as did as a brief chat between lists (Experiment 2). A number-search task between lists produced neither costs nor benefits (Experiment 3), suggesting that mere distraction is insufficient for inducing mental context change. Our findings support the claim that mental context change underlies both intentional and unintentional forgetting.     

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。     

Intention superiority effect on implicit memory of shopping lists: Activation and inhibition processes

Intentional memory is defined as the ability to remember to perform intentions in the future. Forming an intention such as “shopping” activates access to memories related to the products on the shopping list. As Intention Superiority Effect (ISE) studies show, these memories are more accessible in semantic and episodic memory, more activated over time and protected from competing representations. The inhibition of competing representations in intentional memory has been little examined so far. In this study we attempt to analyze changes in activation in the recall of products on a shopping list and competitors through implicit memory tasks. Sixty-five participants learned two shopping lists on a computer. Later, they were told to virtually buy one of them (prospective list) and not the other (neutral list). Prior to intentional task execution, they performed an implicit retrieval task in which we manipulated the appearance or not of cues from the intentional list and analyzed the influence of the items from the intentional list on items related to intentional and neutral lists. The main result of this study is that intention retrieval by intentional cues strengthens the activation of products related to the intentional list and/or inhibits competing products related to the neutral list. The inhibition is episodic rather than semantic in nature. The ISE requires the recall of the intention during the retention period through intentional cues for maintaining the intention. This seems to defend automatic recovery theories and not the intention persistence hypothesis. Also, the results are better explained by the directed forgetting paradigm rather than by the retrieval-induced forgetting paradigm.     

Directed forgetting of autobiographical events

Two diary experiments demonstrated directed forgetting (DF) of autobiographical events, previously observed only for less complex memory items. Using a 2-week diary paradigm, we compared recall between a group of participants who were directed to forget Week 1 memories (forget group) and a group who did not receive a forget instruction (remember group). In Experiment 1, the forget group remembered fewer items from Week 1 than did the remember group. The effect was observed for negative and positive valence events, as well as for high and low emotional intensity events. The effect was replicated in Experiment 2 despite a memorable holiday (Valentine's Day) that occurred during the manipulation week. Forget participants remembered fewer low emotional intensity items in Experiment 2. We conclude that intentional forgetting is a plausible explanation for the loss of some autobiographical memories.     

BRIEF REPORT Forgetting “murder” is not harder than forgetting “circle”: Listwise-directed forgetting of emotional words

The list-method directed forgetting (DF) paradigm has attracted the attention of clinical psychologists because it is widely believed that a retrieval inhibition mechanism underlies its effects. Thus, the idea is that people are capable of intentionally forgetting negative emotional material. On the other hand, there are reasons to believe that negative stimuli are relatively resistant to forgetting. The present experiment compared listwise DF of emotional and neutral words in healthy college students. A modified procedure (i.e., a simulated computer crash) showed a reliable DF-effect in that list 1 recall was larger under remember than forget instructions whereas the reverse was true for list 2 recall. Emotionality did not modulate the magnitude of this effect. Thus, negative emotional material is not resistant to forgetting. Although overall, the present findings are in line with a retrieval inhibition interpretation (i.e., decreased access to list 1 material), attentional focusing during list 2 learning may provide a sufficient explanation.     

提取抑制对错误记忆的影响

该研究探讨提取抑制能否减少错误记忆的发生.以自编的DRM词表为实验材料,实验1采用有意遗忘范式（有意抑制）,实验2采用部分线索效应范式（无意抑制）.实验1结果发现：关键诱饵在“记住”条件下的错误回忆成绩显著高于“遗忘”条件下的错误回忆成绩;学过项目在“记住”条件下的正确回忆成绩显著高于“遗忘”条件下的正确回忆成绩.实验2结果发现：关键诱饵在“无部分线索”条件下的错误回忆成绩显著高于“部分线索”条件下的错误回忆成绩;学过项目在“无部分线索”条件下的正确回忆成绩显著高于“部分线索”条件下的正确回忆成绩.研究结果提示：有意和无意两种提取抑制都可以降低错误记忆,结果支持基于激活与监测的双加工理论的观点.     

The crucial role of postcue encoding in directed forgetting and context-dependent forgetting

People can intentionally forget previously studied material if, after study, a forget cue is provided and new material is learned. It has recently been suggested that such list-method directed forgetting arises because the forget cue induces a change in internal context and causes context-dependent forgetting of the studied material (L. Sahakyan & C. M. Kelley, 2002). The authors compared directed forgetting and context-dependent forgetting by examining whether, like a forget cue, a change in internal context needs subsequent learning of new material to be effective. Participants studied an item list and, after study, received a remember cue or a forget cue or their internal context was changed through an imagination task. In each condition, half the participants learned a second list, and the other half fulfilled an unrelated distractor task. Both the forget cue and the change in internal context induced forgetting of the first list only when learning of the second list was interpolated. These results suggest that postcue encoding of new material is crucial for both directed forgetting and (some forms of) context-dependent forgetting.     

Directed forgetting of negative performed actions is difficult: A behavioural study

Strong evidence suggests that both performing actions and emotional stimuli can enhance memory by capturing attention. However, the synergetic effect of the two factors on directed forgetting has not been assessed. In this study, we used an item-method directed forgetting paradigm to examine the forgetting of emotional materials depending on whether actions were performed. The results showed that action performance influenced the directed forgetting of emotional words. Specifically, when actions were performed there was a directed forgetting effect for neutral and positive words but not for negative words. In comparison, for verbal tasks, directed forgetting was observed for all words. The elaborative encoding prior to the remember/forget instructions and the influence of negative emotion on attentional inhibition after the presentation of the instructions together suggest that it is more difficult to intentionally forget negative performed actions.     

Are the costs of directed forgetting due to failures of sampling or recovery? Exploring the dynamics of recall in list-method directed forgetting

This study investigated the costs of directed forgetting within the framework of a search model. In such models, retrieval failure can occur at either the sampling or the recovery stage of recall. Multiple measures of performance were employed to answer two primary questions of interest: (1) Where does the locus of forgetting occur in the directed forgetting paradigm? and (2) What current theory of directed forgetting can best account for the pattern of data observed? Converging evidence from these measures suggested that the costs of directed forgetting are the result of sampling issues during retrieval. Further, these results were best explained by a contextual-change account that argues an instruction to forget creates a break in context causing individuals to sample more items at retrieval. It is argued that the retrieval deficits observed in list-method directed forgetting paradigms are due, in part, to the fact that individuals sample a greater number of items (that include both targets and intrusions) during retrieval in the forget-condition, thereby creating greater response competition compared with retrieval in the remember-condition.     

不同学习成绩的小学生有意遗忘过程的实验研究

该研究的实验材料为单字和双字词,利用字表方式呈现。被试为小学六年级的30名学生,按学习成绩好和差各选15名。实验结果为,（1）对单字材料,被试既对要记忆的项目进行了有意的复述,又对指示遗忘的材料产生了提取抑制;对双字词材料,被试只有对指示遗忘的材料产生提取抑制,而没有对要记忆的项目进行有意复述;（2）学习成绩好的学生的有意遗忘的抑制能力明显高于学习成绩差的学生。