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

我们都有想要忘记的经历，尽管我们常常能够将这些想法从脑海中推开，但当面对合适的提醒时，它们仍然会偶尔出现。我的大部分研究都集中在描述一些基本机制上，通过这些机制，当面对这样的提醒时，不想要的记忆就不会出现在脑海中，或者当它们出现时，就会被赶出脑海。以任何一种方式控制记忆都会降低目标记忆在将来再次出现在脑海中的可能性。然而，关于如何实施这些机制，仍有许多问题有待了解。因此，我的长期目标是开发一种神经认知模型，描述在编码和检索中控制不需要的记忆所涉及的机制。我过去的研究表明，在接触图像后不久，试图忘记图像涉及到一种或多种活跃的机制，这些机制与将注意力从图像的表现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环境，类似的机制是否控制不需要的检索，以及在编码或检索时控制记忆是否以类似的方式影响不需要的记忆的表示，仍然是未知的。本提案将在健康的大学年龄人口中解决这些问题，采用多种方法，重点是操纵参与者制定任务指示的方式，同时使用行为或心理生理学措施来表征所涉及的认知机制的性质。考虑到这一点，本建议的目标是：1)隔离在编码时制定记忆控制机制的情况，并将其推广到检索控制；2)利用心理生理标记追踪这些机制的时间特性及其与成功控制的关系；并且，3)将对不需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联系起来。通过在编码和检索中应用的记忆控制的神经认知机制之间的相似之处，这项工作将为对记忆控制背后的基本认知机制以及如何在各种条件下灵活地实施这些机制来控制不想要的经历的共同理论理解提供强大的刺激。在此过程中，这一研究项目将为我们理解人类思维的运作方式提供基础知识，并为我们理解其他更高层次的认知能力提供信息。

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.