scholarly journals Time is of the essence: Exploring temporal and spatial organisation in episodic memory

2021 ◽  
pp. 174702182199382
Author(s):  
Dan PA Clark ◽  
Davide Bruno
Keyword(s):  
Episodic Memory ◽  
Recall Performance ◽  
Temporal Contiguity ◽  
Free Recall Task ◽  
Temporal Dimension ◽  
True Nature ◽  
Spatial Contiguity ◽  
Current Series ◽  
Incidental Encoding ◽  
Temporal Organisation

There is disagreement in the literature as to whether episodic memory maintains an inherent temporal organisation, that is, whether learned items are necessarily organised along some temporal dimension or whether temporal organisation is a task-specific occurrence. The current series of experiments explored this issue. In Experiment 1, we tested whether temporal or spatial contiguity was present in an incidental encoding task where either strategy (but not both together) could be employed at test. In Experiment 2, we attempted to facilitate the use of a spatial retrieval strategy at test by asking participants to recall the location where target items had been displayed at study, after incidental encoding. Experiment 3 explored the role of study-test congruency by informing participants at encoding that they would be tested on either their memory for the temporal sequence or spatial locations, and then testing both at retrieval. Finally, Experiment 4 employed a masking task at encoding to ensure participants could not predict the true nature of the task, despite it being incidental, and a surprise free recall task. Predominantly, participants displayed recall performance consistent with temporal contiguity, although there was evidence for spatial contiguity under certain conditions. These results are consistent with the notion that episodic memory has a stable and predictable temporal organisation.

scholarly journals Hippocampal theta codes for distances in semantic and temporal spaces

2019 ◽  
Vol 116 (48) ◽  
pp. 24343-24352 ◽  
Author(s):  
Ethan A. Solomon ◽  
Bradley C. Lega ◽  
Michael R. Sperling ◽  
Michael J. Kahana
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Dynamic Range ◽  
Recall Performance ◽  
Spatial Navigation ◽  
Mapping Function ◽  
Cognitive Maps ◽  
Free Recall Task ◽  
Neurosurgical Patients ◽  
Hippocampal Theta

The medial temporal lobe (MTL) is known to support episodic memory and spatial navigation, raising the possibility that its true function is to form “cognitive maps” of any kind of information. Studies in humans and animals support the idea that the hippocampal theta rhythm (4 to 8 Hz) is key to this mapping function, as it has been repeatedly observed during spatial navigation tasks. If episodic memory and spatial navigation are 2 sides of the same coin, we hypothesized that theta oscillations might reflect relations between explicitly nonspatial items, such as words. We asked 189 neurosurgical patients to perform a verbal free-recall task, of which 96 had indwelling electrodes placed in the MTL. Subjects were instructed to remember short lists of sequentially presented nouns. We found that hippocampal theta power and connectivity during item retrieval coded for semantic distances between words, as measured using word2vec-derived subspaces. Additionally, hippocampal theta indexed temporal distances between words after filtering lists on recall performance, to ensure adequate dynamic range in time. Theta effects were noted only for semantic subspaces of 1 dimension, indicating a substantial compression of the possible semantic feature space. These results lend further support to our growing confidence that the MTL forms cognitive maps of arbitrary representational spaces, helping to reconcile longstanding differences between the spatial and episodic memory literatures.

scholarly journals Hippocampal theta codes for distances in semantic and temporal spaces

2019 ◽  
Author(s):  
Ethan A. Solomon ◽  
Bradley C. Lega ◽  
Michael R. Sperling ◽  
Michael J. Kahana
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Dynamic Range ◽  
Recall Performance ◽  
Spatial Navigation ◽  
Mapping Function ◽  
Cognitive Maps ◽  
Free Recall Task ◽  
Neurosurgical Patients ◽  
Hippocampal Theta

ABSTRACTThe medial temporal lobe (MTL) is known to support episodic memory and spatial navigation, raising the possibility that its true function is to form “cognitive maps” of any kind of information. Studies in humans and animals support the idea that the hippocampal theta rhythm (4-8 Hz) is key to this mapping function, as it has been repeatedly observed during spatial navigation tasks. If episodic memory and spatial navigation are two sides of the same coin, we hypothesized that theta oscillations would also reflect relations between explicitly nonspatial items, such as words. We asked 189 neurosurgical patients to perform a verbal free-recall task, of which 96 had indwelling electrodes placed in the MTL. Subjects were instructed to remember short lists of sequentially-presented nouns. We found that hippocampal theta power and connectivity during item retrieval coded for semantic distances between words, as measured using word2vec-derived subspaces. Additionally, hippocampal theta indexed temporal distances between words after filtering lists on recall performance, to ensure adequate dynamic range in time. Theta effects were only noted for semantic subspaces of 1-dimension, indicating a substantial compression of the possible semantic feature space. These results lend further support to our growing confidence that the MTL forms cognitive maps of arbitrary representational spaces, reconciling longstanding differences between the spatial and episodic memory literatures.

Articulatory Rehearsal Is More Than Refreshing Memory Traces

2013 ◽  
Vol 60 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Ryoji Nishiyama ◽  
Jun Ukita
Keyword(s):  
Free Recall ◽  
Recall Performance ◽  
Verbal Working Memory ◽  
Verbal Information ◽  
Free Recall Task ◽  
Study Item ◽  
Phonological Representations ◽  
Memory Traces ◽  
Short Period ◽  
Serial Position Curves

This study examined whether additional articulatory rehearsal induced temporary durability of phonological representations, using a 10-s delayed nonword free recall task. Three experiments demonstrated that cumulative rehearsal between the offset of the last study item and the start of the filled delay (Experiments 1 and 3) and a fixed rehearsal of the immediate item during the subsequent interstimulus interval (Experiments 2 and 3) improved free recall performance. These results suggest that an additional rehearsal helps to stabilize phonological representations for a short period. Furthermore, the analyses of serial position curves suggested that the frequency of the articulation affected the durability of the phonological representation. The significance of these findings as clues of the mechanism maintaining verbal information (i.e., verbal working memory) is discussed.

scholarly journals EXPRESS: Stimulus novelty, task demands, and strategy use in episodic memory

2020 ◽  
pp. 174702182098030
Author(s):  
Otto Waris ◽  
Daniel Fellman ◽  
Jussi Jylkkä ◽  
Matti Laine
Keyword(s):  
Episodic Memory ◽  
Task Performance ◽  
Recall Performance ◽  
Cognitive Task ◽  
Memory Performance ◽  
Memory Task ◽  
Strategy Use ◽  
Skill Learning ◽  
Cognitive Task Performance ◽  
And Task

Cognitive task performance is a dynamic process that evolves over time, starting from the first encounters with a task. An important aspect of these task dynamics is the employment of strategies to support successful performance and task acquisition. Focusing on episodic memory performance, we: (1) tested two hypotheses on the effects of novelty and task difficulty on strategy use; (2) replicated our previous results regarding strategy use in a novel memory task; and (3) evaluated whether repeated open-ended strategy queries affect task performance and/or strategy use. The present pre-registered online study comprised 161 adult participants who were recruited through the Prolific crowdsourcing platform. We employed two separate 5-block list learning tasks, one with 10 pseudowords and the other with 18 common nouns, and collected recall performance and strategy reports for each block. Using Bayesian linear mixed effects models, the present findings (1) provide some support for the hypothesis that task-initial strategy development is not triggered only by task novelty, but can appear also in a familiar, moderately demanding task; (2) replicate earlier findings from an adaptive working memory task indicating strategy use from the beginning of a task, associations between strategy use and objective task performance, and only modest agreement between open-ended vs. list-based strategy reports; and (3) indicate that repeated open-ended strategy reports do not affect objective recall. We conclude that strategy use is an important aspect of memory performance right from the start of a task, and it undergoes development at the initial stages depending on task characteristics. In a larger perspective, the present results concur with the views of skill learning and adaptivity in cognitive task performance.

scholarly journals A Feasibility Study on the Use of the Method of Loci for Improving Episodic Memory Performance in Schizophrenia and Non-clinical Subjects

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Elisa Sousa ◽  
Yacine Mahdid ◽  
Mathieu Brodeur ◽  
Martin Lepage
Keyword(s):  
Episodic Memory ◽  
Recall Performance ◽  
Memory Performance ◽  
Training Session ◽  
Word List ◽  
Future Research ◽  
Healthy Individuals ◽  
Method Of Loci ◽  
Words And Images ◽  
Memory Monitoring

We investigated the feasibility of a short intervention using the Method of Loci (MoL), a well-known visuospatial mnemonic, to improve episodic memory recall performance in schizophrenia. The MoL training protocol comprised encoding and recall of two lists of items (words and images), a training session and practice with MoL. Then, participants had the opportunity to put into practice the newly learned MoL and were instructed to encode and recall two new lists of items using. This approach was first validated with healthy individuals (N = 71). Subsequently, five individuals with schizophrenia completed the protocol. Improvement in healthy individuals was observed for the word list (Wilcoxon effect size r = 0.15). No significant memory improvement was denoted in the schizophrenia group, possibly due to participants' difficulties using the method efficiently and due to fatigue. The MoL seems to require episodic memory, working memory monitoring and executive functions, making it suboptimal for a population with impairments in all those domains. Future research should examine the use of other strategies, better suited for individuals with cognitive impairments like those found in schizophrenia.

scholarly journals [Pre-Print] Evaluating Recall Error in Preschoolers: Category Expectations Influence Episodic Memory for Color

2020 ◽  
Author(s):  
Kimele Persaud ◽  
Carla Macias ◽  
Pernille Hemmer ◽  
Elizabeth Bonawitz
Keyword(s):  
Episodic Memory ◽  
Recall Performance ◽  
Strong Support ◽  
Similar Process ◽  
Prototype Model ◽  
Individual Subject ◽  
Color Category ◽  
Limited Memory ◽  
Significant Difference ◽  
Category Knowledge

Despite limited memory capacity, children are exceptional learners. How might children engage in meaningful learning despite limited memory systems? Past research suggests that adults integrate category knowledge and noisy episodic traces to aid recall when episodic memory is noisy or incomplete (e.g. Hemmer & Steyvers, 2009). We suspect children utilize a similar process but integrate category and episodic traces in recall to a different degree. Here we conduct two experiments to empirically assess children’s color category knowledge (Study 1) and recall of target hue values (Study 2). In Study 1, although children’s generated hue values appear to be noisier than adults, we found no significant difference between children and adult’s generated color category means (prototypes), suggesting that preschool-aged children’s color categories are well established. In Study 2, we found that children’s (like adult’s) free recall of target hue values regressed towards color category means. We implemented three probabilistic memory models: one that combines category knowledge and specific target information (Integrative), a category only (Noisy Prototype) model, and a target only (Noisy Target) model to computationally evaluate recall performance. Consistent with previous studies with older children (Duffy, Huttenlocher, & Crawford, 2006), quantitative fits of the models to aggregate group-level data provided strong support for the Integrative process. However, at the individual subject level, a greater proportion of preschoolers’ recall was better fit by a Prototype only model. Our results provide evidence that the integration of category knowledge in episodic memory comes online early and strongly. Implications for how the greater reliance on category knowledge by preschoolers relative to adults might track with developmental shifts in relational episodic memory are discussed.

scholarly journals The temporal contiguity effect predicts episodic memory performance

2010 ◽  
Vol 38 (6) ◽  
pp. 689-699 ◽  
Author(s):  
Per B. Sederberg ◽  
Jonathan F. Miller ◽  
Marc W. Howard ◽  
Michael J. Kahana
Keyword(s):  
Episodic Memory ◽  
Memory Performance ◽  
Temporal Contiguity
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