Trying to forget: Characterizing the mechanisms and consequences of intentional forgetting

我们都有宁愿忘记的经历，尽管我们经常能够将这些想法从脑海中推开，但当面对适当的提醒时，它们仍然会偶尔重新出现。我的大部分研究都集中在描述一些基本机制，通过这些机制，当面对这样的提醒时，不想要的记忆被阻止进入脑海，或者当它们出现时，被从脑海中推开。以任何一种方式控制记忆都会降低目标记忆在未来再次出现的可能性。然而，关于这些机制如何实施，仍有许多问题有待了解。因此，我的长期目标是开发一个神经认知模型，描述编码和提取不需要的记忆的控制机制。我过去的研究表明，试图在曝光后不久忘记一个图像会涉及一种或多种主动机制，这些机制与注意力从该图像的表征和空间位置以及其他时间上接近的信息中撤出有关。然而，足以调用这些机制的情况，是否类似的机制控制不必要的检索，以及是否在编码或检索时控制记忆以类似的方式影响不必要的记忆的表示仍然是未知的。本提案将在一个健康的大学适龄人群中解决这些问题，使用一种组合的方法，专注于操纵参与者制定任务指令的方式，同时使用行为或心理生理措施来表征所涉及的认知机制的性质。考虑到这一点，本研究的目标是：1）分离出记忆控制机制在编码时产生的环境，并将其推广到提取的控制; 2）使用心理生理学标记来跟踪这些机制的时间特性及其与成功控制的关系;以及3）将对不想要的记忆的编码和检索的主动控制与测试中这些记忆的保真度的变化相关联。通过绘制在编码和提取应用的记忆控制的神经认知机制之间的相似之处，这项工作将提供一个强大的刺激，对记忆控制背后的基本认知机制的共同理论理解，以及如何灵活地实施这些机制，以控制在各种条件下不必要的经验。在这样做的过程中，这项研究计划将产生对我们理解人类思维如何工作的基本知识，并告知我们对其他高阶认知能力的理解。

We all have experiences that we would rather forget and although we are often able to push these thoughts from mind, they still re-emerge on occasion when faced with a suitable reminder. Much of my research has focused on characterizing the basic mechanisms through which unwanted memories are prevented from coming to mind when faced with such a reminder or pushed from thought when they do. Controlling memory in either manner reduces the probability of the target memory coming to mind again in the future. However, much remains to be known concerning how these mechanisms are implemented. It is therefore my long-term goal to develop a neurocognitive model characterizing the mechanisms involved in the control of unwanted memories at both encoding and retrieval. My past work has shown that trying to forget an image shortly following exposure engages one or more active mechanisms associated with the withdrawal of attention away from the representation and spatial location of that image as well other temporally proximate information. Yet, the circumstances sufficient to invoke these mechanisms, whether similar mechanisms control unwanted retrieval and whether controlling a memory at encoding or retrieval impacts the representation of an unwanted memory in a similar fashion remains unknown. The present proposal will address these topics in a healthy, university-aged population using a combination of approaches focused on manipulating the manner in which participants enact the task instructions while using behavioural or psychophysiological measures to characterize the nature of the cognitive mechanisms involved. With this in mind, the objectives of this proposal are to 1) isolate the circumstances under which memory control mechanisms are enacted at encoding and generalize them to the control of retrieval; 2) use a psychophysiological marker to track the temporal properties of these mechanisms and their relation to successful control; and, 3) relate active control over the encoding and retrieval of unwanted memories to changes in the fidelity of those memories at test. By drawing parallels between the neurocognitive mechanisms of memory control applied at both encoding and retrieval, this work will provide a powerful stimulus towards a common theoretical understanding of the basic cognitive mechanisms behind memory control and how these mechanisms are implemented flexibly to control unwanted experiences under a variety of conditions. In doing so, this program of research will generate knowledge fundamental to our understanding of how the human mind works and inform our comprehension of other, higher-order cognitive abilities.