David Eagleman/poptech

Time is a Rubbery Thing

An Interview with David Eagleman

David Eagleman is a neuroscientist and author. I interviewed him in 2011 as part of my MetaHack interview series.

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.

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

David: 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.”

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

David: 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.

Avi: What do you make of the experience of Deja Vu?

David: 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.

David Eagleman: Device and method for measuring information processing speed of the brain

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

David: 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.

Avi: There are at least 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 every day?

David: 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 mechanics) 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.”

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

David: 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.

David Eagleman’s short story “Metamorphosis” adapted by Blue Delliquanti