Science of Perception Box
Science of Perception Box

Is Time Real? How Your Brain Perceives the Past with Dr. Lila Davachi

March 6, 2025

AI Summary

5 min read

Is Time Real? How Your Brain Perceives the Past with Dr. Lila Davachi

When Dr. Lila Davachi testified as an expert witness in a court case about a woman who died in a motorcycle accident, she had to explain something counterintuitive: those final seconds of terror likely felt much longer to the victim than clock time would suggest. But the paradox, Davachi explains, is that the memory of those seconds would be fragmented — the central core of the experience hyper-detailed, the surrounding context almost entirely absent. This tension between what we feel in the moment and what we later remember is at the heart of her research on memory, time, and the brain.

Memory Is Not for Remembering

Davachi, a neuroscientist at Columbia University, argues that after 25 years studying memory, she no longer believes its purpose is to help us recall the past. "Memory is there to help us understand the world, to build knowledge," she says. The system is designed to prioritize what matters for survival and discard the rest. Most of what happens in a given day is simply trashed during sleep — not because the brain is failing, but because it's working correctly.

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What you'll learn

  • 1 (00:00) **Opening: The Fluid Nature of Time in Memory** - Dr. Davachi states that time does not really exist in memory beyond a few seconds; it is about attention and mental context.
  • 2 (01:24) **Host Introductions and Personal Connections to Memory** - Co-hosts Heather Berlin and Christoph Koch welcome Dr. Davachi and share their own perspectives on how perception shapes memory.
  • 3 (04:14) **The Emotional Split: Negative vs. Positive Memory Encoding** - Dr. Davachi explains that negative and positive emotions encode memories in fundamentally different ways.
  • 4 (07:57) **The Purpose of Memory: Building Knowledge, Not Just Remembering** - Dr. Davachi redefines memory’s function as a system for building knowledge and updating world models, not for perfect recall.
  • 5 (11:48) **Voluntary Control Over Memory: Can You Choose What to Remember?** - The discussion explores the limits of consciously directing memory toward positive or negative content.
  • 6 (13:57) **Memory Reconsolidation: Rewriting the Past** - Every time a memory is recalled, it becomes labile and open to change, making it a target for therapeutic intervention.
  • 7 (19:13) **Time Perception in High-Arousal Moments: “Bullet Time” in Real Life** - The paradox of time slowing down during terrifying or highly salient events is explained.

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Show Notes

Ever wonder why time seems to fly or crawl? From ancient philosophers to modern neuroscientists, the nature of time has captivated human curiosity. This week on Science of Perception Box, we investigate the relationships among time, memory, and perception. Dr. Davachi shares the mechanisms of how the brain encodes and retrieves memories, including why emotions and feelings play a role in our perception of time. 


Lila Davachi is a prominent neuroscientist known for her research in the field of memory. She earned her PhD from Yale University in 1999 and currently holds a faculty position at Columbia University, where she leads the Davachi Memory Lab. Her work primarily focuses on understanding the processes of memory encoding, consolidation, and retrieval through behavioral and cognitive neuroscientific methods.


Dr. Davachi has made significant contributions to the understanding of how memories are formed and maintained in the brain. She has published extensively in academic journals, with her research being highly cited within the scientific community. In addition to her research, she is actively involved in teaching and mentoring students in psychology and neuroscience.


Dr. Heather Berlin is a neuroscientist, clinical psychologist and Professor of Psychiatry and Neuroscience at the Icahn School of Medicine at Mount Sinai in New York City. 


Dr. Christof Koch is Chief Scientist for the Tiny Blue Dot Foundation as well as the current Meritorious Investigator and Former President of the Allen Institute for Brain Science.


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Episode Chapters: 

(00:00) - Exploring Memory and Perception

(04:19) - The Role of Emotions in Memory

(13:32) - Therapeutic Approaches to Memory

(19:25) - Time Perception and Memory

(24:55) - Impact of the Pandemic on Brain Health

(25:16) - Memory and Context During the Pandemic

(27:34) - The Paradox of Time Perception

(28:28) - Balancing Stability and Change for Mental Health

(29:36) - Flow States and Time Perception

(30:27) - Personal Experiences with Time Distortion

(34:37) - The Construct of Time and Memory

(37:34) - Perception Box Questions

(43:35) - Closing Thoughts

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