JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.

The ability to distinguish existing memories from similar perceptual experiences is a core feature of episodic memory. This ability is often examined using the Mnemonic Similarity Task in which people discriminate memories of studied objects from perceptually similar lures. Studies of the neural basis of such mnemonic discrimination have focused on hippocampal function and connectivity. However, default mode network (DMN) connectivity may also support such discrimination, given that the DMN includes the hippocampus, and its connectivity supports many aspects of episodic memory. Here, we used connectome-based modeling to identify associations between intrinsic DMN connectivity and mnemonic discrimination. We leveraged established discrimination deficits in older adults to test whether such age differences moderate network-wide relationships. Resting-state functional connectivity in the DMN predicted mnemonic discrimination ability outside the MRI scanner, especially among prefrontal and temporal regions and including several hippocampal regions. This predictive relationship was stronger for younger than older adults, with age differences primarily reflecting older adults’ weaker temporal-prefrontal connectivity. These novel associations suggest that broader cortical networks including the hippocampus support mnemonic discrimination. They also suggest that disruptions within the DMN that emerge in healthy aging undermine the extent that the DMN supports this ability. These findings provide the first indication of how intrinsic functional properties of the DMN support mnemonic discrimination.

Memory-guided predictions can improve event comprehension by guiding attention and the eyes to the location where an actor is about to perform an action. But when events change, viewers may experience predictive looking errors and need to update their memories. In two experiments (Ns = 38 and 111), we examined the consequences of mnemonic predictive looking errors for comprehending and remembering event changes. University students watched movies of everyday activities with actions that repeated exactly and actions that repeated with changed features—for example, an actor reached for a paper towel on one occasion and a dish towel on the next. Memory guidance led to predictive looking errors that were associated with better memory for subsequently changed event features. These results indicate that retrieving recent event features can guide predictions during unfolding events, and that error signals derived from mismatches between mnemonic predictions and actual events contribute to new learning.

We examined the effects of interpolated retrieval from long-term memory (LTM) and short-term memory (STM) on list isolation in dual-list free recall and whether individual differences in working memory capacity (WMC) moderated those effects. Ninety-seven subjects completed study-test trials that included two study lists separated by either an exemplar generation task (LTM retrieval) or 2-back task (STM retrieval). Subjects then completed an externalized free recall task that allowed for examination of response accessibility and monitoring. Individual differences in WMC were assessed using three complex span tasks: Operation Span, Reading Span, and Rotation Span. Correct recall and intratrial intrusion summary scores showed no effect of interpolated retrieval on response accessibility or monitoring. However, serial position curves for correct recall of List 1 showed larger primacy in the 2-back than exemplar generation task for high-WMC subjects. We interpret these results from a context change perspective as showing that interpolated LTM retrieval accelerated context change for subjects who processed context more effectively. We consider the implications of these findings for models of memory.

Recent events are easy to recall, but they also interfere with recall of more distant, non-recent events. Many computational models recall non-recent memories by using the context associated with those events as a cue. But some models do little to explain how people initially activate non-recent contexts in the service of accurate recall. We addressed this limitation by evaluating two candidate mechanisms within the Context-Maintenance and Retrieval model. The first is a Backward-Walk mechanism that iteratively applies a generate/recognize process to covertly retrieve progressively less recent items. The second is a Post-Encoding Pre-Production Reinstatement (PEPPR) mechanism that formally implements a metacognitive control process that reinstates non-recent contexts prior to retrieval. Models including these mechanisms make divergent predictions about the dynamics of response production and monitoring when recalling non-recent items. Before producing non-recent items, Backward-Walk cues covert retrievals of several recent items, whereas PEPPR cues few, if any, covert retrievals of that sort. We tested these predictions using archival data from a dual-list externalized free recall paradigm that required subjects to report all items that came to mind while recalling from the non-recent list. Simulations showed that only the model including PEPPR accurately predicted covert recall patterns. That same model fit the behavioral data well. These findings suggest that self-initiated context reinstatement plays an important role in recall of non-recent memories and provides a formal model that uses a parsimonious non-hierarchical context representation of how such reinstatement might occur.