工作记忆中的前摄干扰作用研究

发布时间：2018-02-27 07:16

本文关键词： 工作记忆前摄干扰事件相关电位前部N2 前部P3　出处：《汕头大学》2008年博士论文　论文类型：学位论文

【摘要】： 工作记忆是顺利完成高级认知任务的基础。前摄干扰(proactive interference)是对工作记忆具有影响的因素之一,因此考察干扰刺激表征的作用及人们如何克服干扰具有重要的研究意义。本研究包含三个实验。实验一采用工作记忆的选择任务,通过一系列行为实验,系统地考察了靶刺激表征与干扰刺激表征之间的竞争。首先让被试学习一系列字母,接着通过提示刺激指示被试记住一部分字母并忽略其余的字母。被记住的字母成为靶刺激系列,被忽略的字母成为干扰刺激系列。当提示刺激为靶刺激系列时,我们把这种条件叫做“记住”条件;当提示刺激为干扰刺激系列时,我们把这种条件叫做“忘记”条件。提示刺激消失后,屏幕上出现探测刺激,要求被试判断探测刺激是否属于靶刺激系列。研究中,通过调控提示刺激类型和提示刺激与探测刺激之间的时间间隔来检测工作记忆选择的难度。研究发现,在“记住”条件下,提示刺激通过重复呈现靶刺激,增强了靶刺激表征,从而促进了工作记忆的选择,使被试对探测刺激做出更快的判断。然而,“忘记”条件下,尽管提示刺激重复呈现了干扰刺激使干扰刺激的表征得到增强,但却并没有阻碍工作记忆的选择加工过程。这一研究结果为相对激活假说提供了部分支持,说明工作记忆的选择也许更多依赖于靶刺激表征的激活增强,而不是依赖于干扰刺激表征的激活减弱。实验二和实验三采用事件相关电位技术(event-related potential,ERP),分别考察了指导性遗忘任务和最近探测刺激任务中前摄干扰效应的电生理指标及其相关意义。指导性遗忘任务相当于实验一中的“忘记”条件。根据探测刺激的选择将实验条件分为三类。当探测刺激属于靶刺激系列,为正反应条件;当探测刺激是当前测试中没有出现过的项目,为负反应条件;当探测刺激是被“忘记”的项目,则为干扰条件。我们认为干扰条件与负反应条件之间的差异就是前摄干扰效应。最近探测刺激任务中,首先要求被试学习四个字母,随后出现探测刺激,要求被试判断探测刺激是否属于刚才学习过的字母。在这个任务中,为了控制探测刺激的熟悉性,使每个测试中的2个学习字母都与上一轮测试中的两个字母相同,从而形成以下几种实验条件:如果探测刺激在前一个测试及当前测试中都出现过,就属于熟悉性正反应;如果探测刺激仅在当前测试中出现过,属于非熟悉性正反应;如果探测刺激在前一个测试中出现过,但不属于当前测试中的学习项目,属于熟悉性负反应;如果探测刺激在当前测试及最近的前两个测试中都没有出现过,属于非熟悉性负反应。在这个任务中,熟悉性负反应与非熟悉性负反应的差异反映了前摄干扰效应。实验二的结果发现,干扰条件比负反应条件有更大的错误率和延长的反应时。电生理证据方面,在额中央区发现一个N2成分,其波峰在探测刺激出现后300毫秒左右达到最大,并且N2波幅在不同的实验条件下有一定差异,其中干扰条件的N2波幅显著小于负反应条件下的N2波幅。随后的P3波幅对不同的实验条件无差异,但正反应条件的潜伏期要早于负反应和干扰条件。通过分析,我们认为这个分布在额中央区的N2成分代表了前摄干扰的解决。同时,这个负波也说明干扰的解决过程与靶/非靶刺激的辨别发生在同一时间窗口。本研究为基于脑成像研究的偏向竞争模型提供了初步的电生理证据。实验三也发现了位于脑前部区域的N2和P3成分。对于N2波幅,发现了显著的正、负反应条件差异,正反应条件的N2波幅要小于负反应条件。而两种正条件之间与两种负条件之间没有N2波幅的显著差异。此外,两种正反应的P3潜伏期均显著小于两种负反应下的P3潜伏期。对熟悉性负反应和非熟悉性负反应的P3波幅进行分析,发现涉及前摄干扰的熟悉性负反应P3波幅减小。因此我们认为,在这个任务中,P3的波幅变化反映了前摄干扰的解决过程。结合实验二和实验三的结果,我们认为在本研究中,前部N2和P3成分分别代表了双重加工理论中的两个过程:熟悉性信息加工和信息回忆。根据双重加工理论,再认是基于熟悉度及信息回忆的一种综合判断,并且对熟悉度信息的提取要早于对情境信息的提取。由于指导性遗忘任务和最近探测刺激任务中的记忆负荷不同,并且干扰刺激的表征激活强度也不同,因此两种任务中前摄干扰发生作用和被解决的时程也有所不同。在两个实验中,反映干扰效应的电生理成分波幅都有所减小,说明干扰的解决也许并非需要额外心理努力的抑制过程。这与实验一的结果也是一致的,即正确的工作记忆选择是通过对靶刺激表征的激活增强来实现的,而不是依靠干扰刺激表征的激活减小。
[Abstract]:Working memory is the basis for successful completion of advanced cognitive tasks. Proactive interference is one of the factors that influence working memory. Therefore, it is of great importance to investigate the role of interference stimulus and how to overcome interference.
This study includes three experiments. Experiment using a selection task of working memory, through a series of experiments, systematically studied between target stimuli representation and distractors representation competition. First let the participants learn a series of letters, followed by a cue indicating subjects to remember some of the letters and to forget the others. Remember the letters become the target stimulus series, ignored the letters become interference stimulus series. When the cue target stimulus, we have such a condition called "remember" conditions; when prompted for stimulus interference stimulus, we have such a condition called "forget". Cue disappeared after screen detection stimulus, participants were asked to judge whether the probe stimulus belongs to target stimuli.
In the study, through the regulation between stimulus type and prompt cue and probe stimulus intervals to test selection difficulty in working memory. The study found that in the "remember" conditions, suggesting that stimulation through repetition target stimuli, enhanced target characterization, so as to improve the working memory, the subjects made faster judgment of the probe stimulus. However, "forget" conditions, although the characterization of cue repetition disturbance stimulated interference stimulation is enhanced, but chose not to hinder the process of processing of working memory. This research results provide some support for the hypothesis that the relative activation, enhanced activation of working memory may choose more depending on the characterization of the target stimulus, rather than rely on activation of distractors representation is reduced.
Experiment two and three using the event-related potentials (event-related, potential, ERP) were investigated by electrophysiological interference effect and its significance of directed forgetting task and recent probes task. Directed forgetting task in experiment is equivalent to "forget". According to the conditions of the probe stimulus selection experiment the conditions are divided into three types. When the probe stimulus belongs to the target stimulus series, positive reaction conditions; when the probe stimulus is not seen in the current test items, negative reaction conditions; when the probe stimulus is "forget" project, for the interference conditions. We think the difference between interference and negative reaction conditions is proactive interference effect.
The recent probes task, participants were asked to learn four letters, followed by detection of stimuli, the subjects were required to judge whether the probe stimulus just learning the letters belong to. In this task, in order to control the probe stimulus familiarity, the 2 letters in each test are the same with the two letters on a round of tests, so as to form the following conditions: if the probe stimulus in the first test and the current tests have appeared, is familiar with positive reaction; if the probe stimulus appeared only in the current test, belonging to the non familiar positive reaction; if the probe stimulus in the first appeared in the test too, but does not belong to the current test in the learning project, belongs to the familiar negative reaction; if the probe stimulus in the current test and recent before the two test have not appeared, belonging to the non familiar negative reaction in this task. The difference in the negative reaction of familiarity and unfamiliarity reflects the effect of perturbed disturbance.
The results of the two experiments showed that the interference conditions have a greater error rate and prolonged reaction than the negative reaction conditions. Electrophysiological evidence, found a N2 component in the frontal lobe, its peaks at about 300 ms after stimulus onset detection reaches the maximum, and the amplitude of N2 in different experimental conditions have certain differences among them, interference conditions N2 amplitude significantly less than the negative reaction conditions. Then the amplitude of N2 P3 amplitude differences of different experimental conditions, but the positive reaction conditions to negative response latency and interference conditions. Through the analysis, we think that this distribution represents a proactive interference resolution in the fronto central N2 component at the same time, the negative wave also shows that the solving process and target / non target discrimination occurs in the same time window. This study provides preliminary electrophysiological evidence for biased competition model based on brain imaging studies.
Experiment three also found that the N2 and P3 components in the front of the brain area. For the amplitude of N2, we found significant positive and negative difference of the reaction conditions, reaction conditions are smaller than the amplitude of N2 negative reaction conditions without significant difference. The amplitude of N2 between two and two kinds of conditions are negative conditions. In addition, two the positive reaction of P3 latency were significantly less than two kinds of negative reaction under P3 latency. Between familiar and non familiar negative reaction P3 amplitude analysis, found to be involved in proactive interference familiar negative response amplitude of P3 decreases. Therefore, in this task, the amplitude changes of P3 reflect proactive interference resolution.
In combination with the results of experiment two and three, we believe that in this study, anterior N2 and P3 component respectively represent two dual process theory: familiar with information processing and information memory. According to the dual process theory, recognition is a comprehensive judgment of familiarity and recall of information based on the extraction and familiarity with the information earlier in the extraction of context information. The directed forgetting task and memory load recent probes task, and characterization of interference stimuli activation intensity is different, so the two tasks in the proactive interference effect was solved when the process is also different. In the two experiment electrophysiological components, reflect the amplitude of interference effect is reduced, indicating inhibition solution may not need extra mental effort. This is consistent with the experimental results of a work, namely the right note Memory selection is achieved by activating the enhancement of the target stimulus characterization, rather than relying on the activation reduction that interferes with the stimulus characterization.

【学位授予单位】：汕头大学
【学位级别】：博士
【学位授予年份】：2008
【分类号】：R33

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