Summary: A new review explores how episodic memories are formed, stored, and reshaped over time, revealing why our recollections of past events often change. Rather than functioning like fixed files, memories consist of multiple components that can lie dormant until triggered by environmental cues.
When retrieved, these components blend with general knowledge, past experiences, and current context, creating updated versions of the original event. The findings help explain memory distortion and offer insights for mental health, learning, and legal settings where accuracy matters.
Key Facts
- Dynamic Memories: Episodic memories are continually updated, not stored as perfect copies.
- Trigger-Based Recall: Hidden memory traces become conscious only when activated by cues.
- Real-World Impact: Memory reshaping affects mental health, education, and legal decision-making.
Source: University of East Anglia
A study from the University of East Anglia is helping scientists better understand how our brains remember past events – and how those memories can change over time.
A new paper published today explores episodic memory – the kind of memory we use to recall personal experiences like a birthday party or a holiday.
The team say their work has important implications for mental health, education, and legal settings where memory plays a key role.
Working collaboratively with the University of Texas in Dallas, the team show that memories aren’t just stored like files in a computer.
Instead, they’re made up of different parts. And while some are active and easy to recall, others stay hidden until something triggers them.
Importantly, the review shows that for something to count as a real memory, it must be linked to a real event from the past.
“But even then, the memory we recall might not be a perfect copy,” said lead researcher Prof Louis Renoult, from UEA’s School of Psychology.
“It can include extra details from our general knowledge, past experiences, or even the situation we’re in when we remember it.
“Memories of older events often go through a process called re-encoding, which means the brain updates or reshapes the memory over time. This creates a chain of connections from the original experience to the version of the memory we can access now.
“This work helps us understand why our memories aren’t always reliable and how they can be influenced by time, context, and even our own imaginations.”
How the research happened
The team looked at almost 200 psychology and neuroscience studies about memory representations, as well philosophical papers and recent studies using animal models.
Prof Renoult said: “We wanted to suggest a new way of looking at things by combining ideas from different fields. The goal was to make sense of problems that haven’t been solved yet and spark fresh research.”
A key part of the study focused on how the brain physically stores memories, highlighting the role of the hippocampus – a part of the brain that helps form and organise memories.
The research explains how memory traces in the brain can lie dormant and only become conscious representations when something – typically a cue from the environment – activates that memory trace.
“These conscious representations of our past are typically a combination of retrieved information of the original experience, generic knowledge about the world and information relevant for the current situation,” explained Prof Renoult.
“While memories need to have a causal link to past events to count as memories, they may differ each time they are retrieved.
“This means that memories can and do change. They might become less accurate or include new information, making them feel different from the original event.
A crucial part of our daily lives
“Understanding how memories are formed, stored, and reshaped over time is crucial because memory underpins so much of our daily lives – from learning and mental health to decisions made in courtrooms.
“By revealing that memories are dynamic rather than fixed, this research helps us better understand why they can change and how that impacts the way we think, feel, and act,” he added.
Key Questions Answered:
A: Each retrieval blends original memory traces with generic knowledge and present context, reshaping the memory into a revised version of the past.
A: It must be causally linked to an actual past event, even though the recalled version may include altered or added details.
A: Understanding how memories evolve informs mental health treatment, supports better learning strategies, and highlights the limitations of eyewitness testimony.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this memory and neuroscience research news
Author: Lisa Horton
Source: University of East Anglia
Contact: Lisa Horton – University of East Anglia
Image: The image is credited to Neuroscience News
Original Research: Open access.
“The cognitive neuroscience of memory representations” by Louis Renoult et al. Neuroscience & Biobehavioral Reviews
Abstract
The cognitive neuroscience of memory representations
The present paper considers the cognitive neuroscience of memory from a representational perspective with the aim of shedding light on current empirical and theoretical issues.
We focus on episodic memory, differentiating active versus latent, and cognitive versus neural memory representations. We adopt a causal perspective, according to which a memory representation must have a causal connection to a past event to count as a memory.
We note that retrieved episodic information may nonetheless only partially determine the content of an active memory representation, which can comprise a combination of the retrieved information with semantic, schematic and situational information.
We further note that, especially in the case of memories for temporally remote events, re-encoding operations likely lead to a causal chain that extends from the original experience of the event to its currently accessible memory trace.
We discuss how the reinstatement framework provides a mechanistic basis for the causal linkage between an experience, the memory trace encoding it, and the episodic memory of the experience, highlighting the crucial role of hippocampal engrams in encoding patterns of neocortical activity that, when active, constitute the neural representation of an episodic memory.
Finally, we discuss some of the ways in which a memory can become modified and hence distanced from the episode that precipitated it.
