Schematic memories develop quickly, but are not expressed unless necessary

Raw data, analysis, and manuscript for a behavioral experiment examining the formation and expression of schematic memories

Semantic influences on episodic memory distortions

Stimuli, data and analysis cod

Schematic memories develop quickly, but are not expressed unless necessary

Episodic memory retrieval is increasingly influenced by schematic information as memories mature, but it is unclear whether this is due to the slow formation of schemas over time, or the slow decay of the episodes. To address this, we separately probed memory for newly learned schemas as well as their influence on episodic memory decisions. In this experiment, participants encoded images from two categories, with the location of images in each category drawn from a different spatial distribution. They could thus learn schemas of category locations by encoding specific episodes. We found that images that were more consistent with these distributions were more precisely retrieved, and this schematic influence increased over time. However, memory for the schema distribution, measured using generalization to novel images, also became less precise over time. This incongruity suggests that schemas form rapidly, but their influence on episodic retrieval is dictated by the need to bolster fading memory representations

Semantic influences on episodic memory distortions

Semantic knowledge can facilitate or distort new memories,depending on their alignment. We aimed to quantifydistortions in memory by examining how categorymembership biases new encoding. Across two experiments,participants encoded and retrieved image-locationassociations on a 2D grid. The locations of images weremanipulated so that most members of a category (e.g. birds)were clustered near each other, but some were in randomlocations. Memory for an item’s location was more precisewhen it was near members of the same category.Furthermore, typical category members’ retrieved locationswere more biased towards their semantic neighbors, relativeto atypical members. This demonstrates that the organizationof semantic knowledge can explain bias in new memories

Agency enhances temporal order memory in an interactive exploration game.

Agency has been shown to facilitate episodic memory. However, most paradigms use simple list learning tasks which preclude the ability to characterize more associative forms of memory, such as binding of items into spatial and temporal context. Across two studies, we characterize the role of agency on associative memory formation. We delineate agentive from passive memory encoding by allowing agency participants to play an online text-based game meant to simulate free exploration of objects in different rooms, and yoking each passive participant’s trajectory to an agentive participant, thus equating their exposure to the stimuli. To assess memory differences, we gathered three measures: item descriptions, spatial location, and temporal order. While memory for spatial location and item features did not differ between groups, there was a marked enhancement of temporal order memory in the agentive group across two independent samples. These findings support a model of self-directed learning, in which agency facilitates the binding of items into a temporal context, which allows for the sequential binding of information into continuous narratives

Semantic influences on episodic memory distortions

Prior knowledge can facilitate or distort new episodic memories, depending on their alignment. However, it remains unclear how the structure of semantic memory explains systematic variation in how new memories are formed and retrieved. We aimed to quantify distortions in memory by examining how category membership and typicality bias new memories. Across four experiments, participants encoded and retrieved image-location associations. Most members of a category (e.g. birds) were located near each other, such that participants could learn locations of categories as they encoded specific image locations. Critically, some typical and atypical category members were in random locations. We decomposed location memory into two measures: error, a measure of episodic specificity, and bias towards other category members, a measure of the influence of prior knowledge. First, we found that location memory was more accurate for images that were spatially consistent with their category membership. Second, when images were spatially inconsistent, retrieval of typical category members was more biased towards other category members relative to atypical ones. These effects replicated across three experiments, disappeared when images were not arranged by category, and were stronger than effects observed with images arranged by visual similarity rather than category membership. Our observations provide compelling evidence that memory is a reconstruction of multiple sources of information, integrating memory for specific events with relevant semantic knowledge. Furthermore, systematic differences in the magnitude of this integration suggest that the organization of semantic memory can govern the extent of distortion in new episodic memories

How the Organization of Autobiographical Memories Changes Over Time

Cognitive scientists have discovered much about the acquisition, consolidation, and retrieval of episodic memories; how-ever, much less is known about how memories of our daily experiences are organized, nor how this organization maychange as memories become consolidated. Here, we apply computational network science methodologies to quantify theorganization of recent (within the past year) and remote (5 10 years ago) autobiographical memories and quantitativelyexamine how these networks change over time. We found that remote memories exhibited higher global connectivityrelative to recent memories, and that this increased connectivity is coupled with lower subjective ratings of vividness. Ourresults demonstrate how such cognitive features of episodic memory can be quantitatively examined and shed novel lighton the organization and reconfiguration of episodic memories over time