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Self-knowledge is a type of personal semantic knowledge that concerns one’s self-image and personal identity. It has most often been operationalized as the summary of one’s personality traits (“I am a stubborn person”). Interestingly, recent studies have revealed that the neural correlates of self-knowledge can be dissociated from those of general semantic and episodic memory in young adults. However, studies of “dedifferentiation” or loss of distinctiveness of neural representations in ageing suggest that the neural correlates of self-knowledge might be less distinct from those of semantic and episodic memory in older adults. We investigated this question in an event-related potential (ERP) study with 28 young and 26 older adults while they categorised personality traits for their self-relevance (self-knowledge conditions), and their relevance to certain groups of people (general semantic condition). Participants then performed a recognition test for previously seen traits (episodic condition). The amplitude of the late positive component (LPC), associated with episodic recollection processes, differentiated the self-knowledge, general semantic, and episodic conditions in young adults, but not in older adults. However, in older adults, participants with higher composite episodic memory scores had more differentiated LPC amplitudes across experimental conditions. Moreover, consistent with the fact that age-related neural dedifferentiation may be material and region specific, in both age groups some differences between memory types were observed for the N400 component, associated with semantic processing. Taken together, these findings suggest that declarative memory subtypes are less distinct in ageing, but that the amount of differentiation varies with episodic memory function.

Many studies suggest that information about past experience, or episodic memory, is divided into discrete units called “events.” Yet we can often remember experiences that span multiple events. Events that occur in close succession might simply be linked because of their proximity to one another, but we can also build links between events that occur farther apart in time. Intuitively, some kind of organizing principle should enable temporally distant events to become bridged in memory. We tested the hypothesis that episodic memory exhibits a narrative-level organization, enabling temporally distant events to be better remembered if they form a coherent narrative. Furthermore, we tested whether post-encoding memory consolidation is necessary to integrate temporally distant events. In three experiments, participants learned and subsequently recalled events from fictional stories, in which pairs of temporally distant events involving side characters (“sideplots”) either formed one coherent narrative or two unrelated narratives. Across participants, we varied whether recall was assessed immediately after learning, or after a delay: 24 hours, 12 hours between morning and evening (“wake”), or 12 hours between evening and morning (“sleep”). Participants recalled more information about coherent than unrelated narrative events, in most delay conditions, including immediate recall and wake conditions, suggesting that post-encoding consolidation was not necessary to integrate temporally distant events into a larger narrative. Furthermore, post hoc modeling across experiments suggested that narrative coherence facilitated recall over and above any effects of sentence-level semantic similarity. This reliable memory benefit for coherent narrative events supports theoretical accounts which propose that narratives provide a high-level architecture for episodic memory.

Recent evidence suggests that some simulations of future events are encoded in memory and later recalled as "memories of the future," but the factors that determine the memorability of future simulations remain poorly understood. The current research aimed to test the hypothesis that imagined future events are better memorized when they are integrated in autobiographical knowledge structures. Across two experiments, we found that future events that involved the self were better recalled than future events that involved an acquaintance (Experiment 1), and that future events that were related to personal goals were better recalled than future events that were unrelated to goals (Experiment 2). Although self-reference and personal goals influenced the phenomenological characteristics of future simulations (e.g., their vividness and the clarity of event components), the enhanced recall of self-relevant and goal-relevant simulations was not simply due to these differences in the characteristics of simulations. Taken together, these findings suggest that the integration of simulated events with preexisting autobiographical knowledge is an important determinant of memories of the future.

Knowledge benefits episodic memory, particularly when provided before encoding (Anderson & Pichert in Journal of Verbal Learning and Verbal Behavior, 17(1), 1–12, 1978; Bransford & Johnson in Journal of Verbal Learning and Verbal Behavior, 11(6), 717–726, 1972). These benefits can occur through several encoding mechanisms, one of which may be event segmentation. Event segmentation is one’s ability to parse information into meaningful units as an activity unfolds. The current experiment evaluated whether two top-down manipulations—providing context or perspective taking—influence the segmentation and memory of text. For the ambiguous texts in Experiment 1, half the participants received context in the form of a title, whereas the other half received no context. For the text in Experiment 2, half the participants read from the perspective of a burglar and the other half read from the perspective of a home buyer. In both experiments, participants read the passages, recalled the information, and then segmented the passages into meaningful units. Consistent with previous findings, participants who received context recalled more information compared with those who received no context, and participants in one perspective were more likely to recall information relevant to their perspective. Most importantly, we found that context and perspective facilitated more normative segmentation; however, the differences were small and suggest that effects of top-down processing on the segmentation of text may be modest at best. Thus, event segmentation processes that operate during text comprehension are influenced by semantic knowledge but may be more heavily driven by other factors (e.g., perceptual cues).

The primary and convergent retrieval (PCR) model assumes that the act of successful recall not only boosts associations between the item and retrieval cues but additionally strengthens associations within the item (i.e., between the features of an item), speeding the rate of information retrieval from memory. The latter effect is termed intra-item learning and is a unique benefit of recall practice (i.e., the "testing effect"). Prior work confirmed the prediction that recall practice produces faster subsequent recall than restudy practice even if accuracy is higher following restudy. The current study replicated this result, but also examined the downside of recall practice: that after a failure to recall during practice, participants will be faster in their failure to recall on a subsequent recall test. This prediction was confirmed in a multisession cued recall experiment that collected accuracy and recall latency measurements for no practice, recall practice, or restudy, with an immediate or delayed final test. The linear ballistic accumulator model was fit to latency distributions, and model comparison determined that these effects reflect differences in drift rates, as predicted by the PCR model.

Atkinson and Shiffrin (1968) argued that performance on any memory task reflects the combined influence of both the fixed structure of the memory system and control processes tailored to the specific task. We investigated the role of control processes in governing the temporal contiguity and semantic contiguity effects in free recall-tendencies to organize recall based on proximity in the study list and pre-existing semantic associations. Subjects studied lists that contained four "clusters", each composed of four semantically associated words but presented in random order such that associates were not in adjacent serial positions. Subjects were given either standard free-recall instructions, instructions to focus on order-based associations (i.e., the original order of presentation), or meaning-based associations (i.e., pre-existing semantic relationships). Replicating previous work, lists with strong semantic relationships resulted in a reduced overall temporal contiguity effect when recalled under standard free-recall instructions. However, under meaning-based recall instructions, the temporal contiguity effect was nearly eliminated. Detailed analyses of within-cluster transitions and an order reconstruction task revealed that temporal information was encoded, but control processes prevented it from dominating memory search. These results point to a need for more empirical work exploring how control processes change recall dynamics and for more theoretical work modeling the computational basis of these processes.