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

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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.