An interview with David Eagleman, neuroscientist

Photo: Poptech

David Eagleman is a neuroscientist and author.

Avi Solomon

What fascinates you about the nature of time?

David Eagleman

We all go through life assuming that time is an external river that flows past us. But experiments in my laboratory over the past decade have shown that this is not precisely the case. Time is an active construction of the brain. We can set up simple experiments to make you believe that a flashed image lasted longer or shorter than it actually did, or that a burst of light happened before you pressed a button (even though you actually caused it with the button), or that a sound is beeping at a faster or slower rate than it actually is, and so on. Time is a rubbery thing.

David Eagleman reads his short story "Sum"


How do you account for testimonies of consciousness extending beyond cardiac arrest? What could they imply about the brain?


It's hard to know what to make of these claims. On the one hand, we know that the brain is easily coaxed into hallucinatory states that are taken to be reality: just think of your visually rich, bizarre-but-fully-believed nighttime dreams. On the other hand, although we know a great deal about the details of neurobiology, we have little scientific insight into the existence of private subjective experience -- that is, how cells and chemicals achieve consciousness.

So in the end, most scientists will (probably correctly) dismiss a near-death experience as a trick of the brain in a low-oxygen state. However, the vastness of the mysteries before us requires us to keep a tiny bit of room open for a continual re-visiting of the question. As my colleague Ara 13 writes, “No theory is Babe Ruth. Their numbers never get retired.”


How would you account for the testimonies of a Panoramic Life Review during near-death experiences?


I’ve been collecting people’s experiences about this for a while. When people find themselves in an optionless, life-threatening situation (such a sliding on ice toward an oncoming truck, or skidding toward the edge of a cliff on a motorcycle), they will commonly describe the experience of having all their memories present at once. This is not so much a cinematographic "flashing" of their life before their eyes, but instead a simultaneously present "panorama" of memories. And not necessarily big, important memories, but instead small, banal, perhaps meaningless ones. How can we understand what’s going on here?

First, in the 1950s, neurosurgeon Wilder Penfield stimulated the temporal lobe of patients undergoing brain surgery, and he discovered that a little buzz of electricity in the right spot in the temporal lobe could trigger a vividly experienced memory—such as standing in a parking lot speaking with someone, or listening to a particular symphony. So we know the memories are stored in there. When the brain is driven into an extraordinary situation of impending doom, it moves out of its normal operating range and somehow all these memories bubble into conscious awareness. It may well be that the brain is 'searching' for any possible solution to a very bad problem, and in its desperation pulls out all the stops. I see panoramic memory as a terrific inroad into understanding consciousness.


What do you make of the experience of Deja Vu?


It seems clear that people experiencing deja vu are not actually detecting the future. This is easily demonstrable: the next time a friend says she's experiencing deja vu, quickly pull out twenty dollars and offer it to give it to her if she can tell you what's going to happen next. You won't lose. Instead, your friend will merely be able to report that after something happened she feels as though she knew it was going to happen. So there appears to be nothing time-violating about it. Instead, deja vu appears to be a hiccup of the familiarity systems in the brain -- the same systems that tell you a bizarre situation in a dream is something normal, something you've seen before.


Do you have a generic method for thinking up innovative experiments?


The only general strategy I employ is to avoid the places where everyone else is going. The most delicious fruits in science are often found in the places where no one else is looking. Relatedly, it's an old axiom in science that the exclamation that signals a rich discovery is not "Eureka!", but more often "That's strange." So that's where I try to position myself, around the "that's strange" phenomena.


There are roughly 50 galaxies or 10 trillion stars per person in the currently known universe. Why do you think we all glibly forget this amazing fact? How can we keep wonder alive everyday?


Indeed, I'm often surprised that people aren't talking about these issues all the time. But the reason seems clear enough. Our brains have evolved to deal with issues at our own scales: mates, rivers, apples, rabbits, and so on. Our brains simply weren't built to understand the fabric of reality at the very small scales (quantum mechnics) or the very large (the cosmos). As Blaise Pascal put it, “Man is equally incapable of seeing the nothingness from which he emerges and the infinity in which he is engulfed.”


What advice would you give to a smart kid who's now in high school?


Watch TED talks: smart people will distill their life’s work down to 20 minutes for you. Follow links through infinite trajectories of Wikipedia. Watch educational videos on topics that resonate with you.

There are a million ways to waste time on the net; reject those in favor of ways that teach you exactly what you want to know. Never before have we enjoyed such an opportunity for tailored, individualized education.

And be sure to get off-line often, to take digital sabbaths. As much as the net provides a platter of mankind's learning, there is a different kind of learning to be had from a hike in the woods, the climbing of a tree, an afternoon building a dam in a stream.


  1. His take on NDE is refreshing.
    I always thought of déjà vu experiences as a feeling of familiarity, of having lived the same situation. People who I know and who experienced it also never saw it a premonition. Is this a cultural difference ?
    His other answers are intelligent and stimulating: they also reveal how much, in spite of all his experience and knowledge, he has to rely on speculation as we really know precious little of most things.

  2. Oh Man! So this is the guy that wrote Sum? 

    If you an track them down, look for episodes of Wiretap (Jonathan Goldstein – CBC Radio) from I think around Season 6 which has loads of excerpts read as introductions to the episode. The stories are some of the most tragic and poetic allegories for our small,  intimate existence I have ever heard. 

    One of my favorites was about how when we die, Heaven is populated only with people that we met in life. At first we are happy to be with all these people for eternity, but then a deeper sadness inevitably sets in as we come to the realization that we could have met more…

  3. A few weeks ago I watched a really fascinating presentation by Eagleman on the nature of subjective time and how we “live in the past” (we don’t see things until about 80 ms after the light reaches our eyes, and a perception at one moment is actually influenced by slightly later events): Definitely recommend checking it out if you find this stuff interesting.

    1. Only from a non-linear, non-subjective viewpoint. 

      (Actually, according to the OP, its wibblly wobbly from a SUBJECTIVE viewpoint. But the OP isn’t a timelord)

  4. Interesting. A common experience of the elasticity of time depending on subjetivity is why ten minutes of waiting the bus in the rain on a monday morning seem ethernal compared to the ten minutes one spends awake just after the alarm clock buzzed.

  5. Time may indeed be a rubbery thing, but Eagleman seems to be discussing our *perception* of time rather than the *nature* of time. 

  6. This is too ‘duh’ to be tolerable. Anyone who has sat through a three hour lecture, run a race, had a first kiss – let alone dropped acid – could tell you that.

  7. As someone who helps folks use their time more effectively, the concept of time as an active construction of the brain, is quite liberating. I’m going to think about ways to apply this in the workplace. How strange! 
    Great article and links. 
    dawn groves

  8. huh.  So that’s what he looks like.  The New Yorker did an amazing profile of him 2-3 mos. back.  Apparently it was a fall from the roof as an adolescent that kind of fixated him on the subject of time.  Kind of like a reverse Newton’s apple.

  9. His description of déjà vu is very limited and ill-informed. In my experience, and it those  I’ve heard, there is no such thing as “I am experiencing déjà vu” except as the disorienting aftertaste of the experience in which events seemed locked, known, predictable, utterly inevitable and during which no such discussion (e.g. the $20 bet) would be possible. So it’s a bit of a straw man.

    1.  I’ve had deja vu many times, sometimes even recursive deja vu (I’m having deja vu I’m having deja vu I’m having deja vu, ad infinitum). In my experience there is such a thing as “I am experiencing deja vu”, I’ve said those very words while experiencing deja vu. There are two specific scenarios I can distinctly remember doing this more than once. In one I’m in a hallway alone and say it to myself. In the other I’m in the kitchen with someone else, I find this one the most interesting because I have recursive deja vu of telling the other person I’m having deja vu. It’s like my memory and my subjective experience of the moment are two mirrors that line up into an infinite reflection of self-awareness. Having done this a few times around the same person I know each experience is distinct because they remember previous incidents, but even though it has actually happened before they don’t remember the specifics well enough to share my subjective experience of deja vu. It’s almost like being in a dream, there’s that kind of sense that the other person is not entirely real but doesn’t know it.

  10. Great interview, Avi.  Thank you.  Love the last question and answer.  I think some of the more ornery people in this thread should take that answer more to heart.  ^_^

  11. I’ve looked around on google for this, but I have yet to really figure out what it is…Does anyone else have this happen to them where you are just minding your own business (basically doing any random task or activity) and then a past thought/memory just POPS into your consciousness?  I have that happen from time to time and these memories seem to come out of the blue.

    For instance, I will be bending over to pick up my son and then a memory of walking down my high school’s hallway will just APPEAR in my consciousness and I have NO IDEA where that came from.  (That is just a random example; it is not what happens every time I have one of these events.  The memory can be absolutely anything from my past.)

    They’re usually pretty mundane details of my past; they’re nothing traumatic or memorable whatsoever…

    What the hell is that called? 

  12. Interesting. I have been having this weird illusion when I punch in the code to enter our gate. If I do it without really paying attention, it seems as if the display reacts before I press the last button. I’ve done it slowly just to test, and it of course waits until I enter the last digit of the code before it displays the “Access Granted” text. But when I am punching buttons quickly without really thinking about it, it seems as if the display happens right before I press the last digit. Nice to have somewhat of an explanation of this illusion.

  13. Either I’m misunderstanding Eagleman entirely, or the following is patently false:

    “Our brains simply weren’t built to understand the fabric of reality at the very small scales (quantum mechnics) or the very large (the cosmos). …”

    Molecular theory has existed since the 5th century BCE. In the early 19th century, Amedeo Avogadro was speculating about what we now call “atoms.”

    In other words, for more than 2000 years, humanity was able to apprehend the “fabric of reality at the very small scales” without having the technological means for *directly* observing the “fabric of reality” in question.

    If the general public has difficulty “seeing” the world in terms of quantum mechanics, it’s simply because this way of seeing the world is comparatively new. The pathogenic theory of medicine seemed counter-intuitive to a world that traditionally regarded disease as having to do with evil spirits and/or the displeasure of Almighty God.

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