Podcast Summary: Steve Ramirez, “How to Change a Memory: One Neuroscientist’s Quest to Alter the Past” (Princeton UP, 2025)

Podcast: New Books Network
Host: Caleb Zakrin
Guest: Steve Ramirez, Associate Professor of Psychological and Brain Sciences, Boston University
Release Date: January 19, 2026

Episode Overview

In this engaging episode, Steve Ramirez discusses his new book, How to Change a Memory, which explores the neuroscience of memory—how memories are formed, stored, manipulated, and even artificially altered. Through personal stories and detailed scientific insights, Ramirez reveals the physical reality of memories, the phenomenon of memory malleability, and the future of memory research, including implications for mental health and artificial intelligence.

Steve Ramirez’s Journey into Memory Science

• Personal Origin Story (01:34–04:09)
  • Initially unsure of his career path, Ramirez found himself uninterested in his first research lab, which left him discouraged with science.
  • Joining Howard Eichenbaum’s lab at BU, which studied learning and memory, ignited his passion:

    “It was that kind of camaraderie, plus the neuroscience of memory, that initially had me … hooked.” (03:15, Ramirez)

  • Surrounded by supportive mentors and peers, he discovered his lasting fascination with the mysteries of memory.

Understanding Memory: The Engram

• What Is an Engram? (04:09–06:15)
  • An “engram” is described as the physical manifestation or trace of a memory in the brain.
  • Ramirez likens the engram to “a mini holy grail of memory research,” representing the measurable changes resulting from experiences:

    “All experience ... leaves some kind of measurable change in the brain. ... That measurable change is sometimes transformed into the thing that becomes a memory.” (04:36, Ramirez)

  • The dynamic, ever-changing nature of the brain makes “hitting” or observing an engram akin to “trying to hit this receding, ever-moving target.” (05:05, Ramirez)

Where Memories Are Stored: The Evolving Neuroscience

• Short-term vs. Long-term Memory (06:15–10:05)
  • Traditional view: Memories begin in the hippocampus and are then stored in the cortex (“systems consolidation”).
  • Newer research shows memories are distributed throughout the brain in what Ramirez calls a “constellation” of activity, always shifting:

    “Any memory recruits the brain, high and low, left and right, ancient and modern, and it recruits a constellation of activity throughout the brain.” (07:36, Ramirez)

Memory Malleability and Recollection

• How and Why Memories Change (10:05–14:06)

  • Each time a memory is recalled, it's susceptible to change—details become warped, sometimes unconsciously:

    “Memories aren’t like a video of the past. … It’s more as a kind of reconstruction.” (10:48, Ramirez)

  • Malleability can be benign (misremembering wedding details) or significant (in legal scenarios).

• Triggers and Retrieval (14:06–17:16)

  • Memories require triggers—sensory (smell, sound), locations, emotions, or even internal thoughts—to be recalled.
  • Ramirez uses the domino analogy: “Once those brain cells are activated, that’s the domino that got flicked over that then causes the recollection of that given memory.” (14:55, Ramirez)
  • Types and patterns of triggers show the complexity and interconnected nature of memory storage and recall.

Artificial and False Memories

• Lab Experiments in Memory Manipulation (17:16–23:10)
  • Groundbreaking research found that activating specific memory-encoding cells with light could bring back or alter a memory (e.g., making a mouse fearful of a place where nothing bad happened):

    “When we artificially activated just those brain cells, that was enough to bring that memory back to life.” (20:10, Ramirez)

  • Implanting a false memory required pairing the artificial reactivation of a “safe” context with a negative real-life experience, causing animals later to fear that neutral context.

Ethical & Clinical Applications

• Therapeutic Potential (23:10–30:00)
  • Ramirez highlights the dual-use nature of memory manipulation—potential for both harm and therapeutic benefit:

    “Something as elemental and nourishing as water can be used to nourish ourselves... or it could be used to torture someone. ... Imagine memory manipulation...” (23:57, Ramirez)

  • Using positive memory activation in animal models of depression and anxiety shows promise in alleviating symptoms like anhedonia (inability to feel pleasure):

    “…when we artificially reactivate a positive memory in those animals, they immediately start seeking out the sugar water. ... It was a lasting intervention.” (27:25, Ramirez)

  • Human application: Simply recalling positive memories can boost mood, motivation, and even creativity.

The Role of Memory in Identity and Imagination

• Memories and the Self (30:00–34:10)
  • Memory shapes identity:

    “Memories ... are the thing that threads and unifies our overall sense of being, our, our identity of ourselves.” (30:37, Ramirez)

  • Memories also serve the adaptive function of enabling us to imagine and plan for the future, drawing on prior experiences as "building blocks":

    “Memories aren’t just looking backwards. Memories are our brain’s way of looking forward in time as well and projecting ourselves into the future.” (32:55, Ramirez)

The Future of Memory Science

• Technological Frontiers and Artificial Enhancement (34:10–41:01)
  • Ramirez is optimistic but realistic about the possibility of “super memories” or brain-chip implants:

    “I definitely don’t like to put any artificial speed limits on science and innovation because we may be surprised on where we, we may not be able to even comprehend the technology of 2000 years from now.” (35:26, Ramirez)

  • Recent experiments demonstrate amnesia reversal in animals, suggesting memories may be “harder to break than we think.” (38:58, Ramirez)

Personal Reflections on Memory

• Living with the Knowledge (41:01–44:05)
  • Ramirez’s research has deepened his appreciation for memory’s role in his own life:

    “…my own memories have just helped me understand my own self literally that much more. … It’s also imbued a deep sense of gratitude because I think I’ve been a lot better … at trying to sit with experience and sit with memories and really savor them for what they’re worth instead of ... trying to rewrite them.” (43:20, Ramirez)

Memory and Artificial Intelligence

• AI, Neural Networks, and Human Memory (44:05–47:26)
  • Draws parallels and distinctions between biological memory and AI systems, noting that current large language models (LLMs) excel at memorization but lack true understanding and experiential time travel:

    “Modern day LLMs are basically like, it’s the. It’s the smartest kid in the room that can memorize everything in the book and regurgitate it back … but what’s missing is understanding.” (44:56, Ramirez)

  • The hope is that future AI might better mirror human memory’s shortcuts and resourcefulness.

Speculation and The Mysterious Brain–Body Connection

• The Whole-Body Memory Hypothesis (47:26–49:24)
  • As neuroscience has expanded the known locations of memory processing from the hippocampus to distributed brain regions, new research hints at body-wide memory traces, including the gut microbiome:

    “As a biological organism, our brain never evolved independently of the rest of the body. ... I would be surprised if we didn’t find traces of a memory in our, the peripheral of our body too.” (48:46, Ramirez)

Memorable Quotes & Moments

• On Memory Manipulation:

  • “We wanted to try to control memory and to try to alter the contents of memory to see if our speculations and guesses of how memory works are actually correct.” (18:27, Ramirez)

• On the Ethics of Memory Technology:

  • “Something as elemental and nourishing as water can be used ... for good or bad. Imagine memory manipulation, which inherently has this negative sci fi ... connotation.” (23:57, Ramirez)

• On Memory’s Persistence:

  • “In many instances of amnesia, it’s the librarian that’s checked out of the library, but the books are still there.” (40:09, Ramirez)

• On the Magic of Triggers:

  • “Outside triggers can bring back worlds to life, and ... our thoughts and moods ... can also reawaken corresponding worlds of memories.” (15:40, Ramirez)

• On Personal Growth:

  • “My own memories have just helped me understand my own self literally that much more. ... It’s also imbued a deep sense of gratitude ... trying to sit with experience ... and really savor them...” (43:20, Ramirez)

Key Timestamps for Notable Segments

• Steve Ramirez’s origin story: 01:34–04:09
• Definition and exploration of engrams: 04:09–06:15
• Changing models of memory storage: 06:15–10:05
• Memory reconstruction and malleability: 10:05–14:06
• How triggers work in memory recall: 14:06–17:16
• Lab creation of artificial and false memories: 17:16–23:10
• Therapeutic directions and positive memory work: 23:10–30:00
• Memory’s link to identity/future planning: 30:00–34:10
• Prospects for memory technology: 34:10–41:01
• Personal experiences as a memory researcher: 41:01–44:05
• AI’s relation to biological memory: 44:05–47:26
• Whole-body memory speculation: 47:26–49:24

Tone and Style

Steve Ramirez is lively, introspective, and often philosophical, easily moving between scientific rigor and personal warmth. Caleb Zakrin guides the conversation with curiosity and encouragement.

Conclusion

This episode provides a fascinating, accessible look into the frontiers of memory science—from the basics of how memories are stored, to the implications of memory modification, to the philosophical significance of memory in shaping the self. Ramirez’s work sits at the intersection of neuroscience, ethics, and technology, suggesting a future where understanding and carefully manipulating memory could play a crucial role in mental health and human potential.