The Brain: The Story of You

by David Eagleman

I used to wonder why our society so rarely talks about it, preferring instead to fill our airwaves with celebrity gossip and reality shows. But I now think this lack of attention to the brain can be taken not as a shortcoming, but as a clue: we’re so trapped inside our reality that it is inordinately difficult to realize we’re trapped inside anything. At first blush, it seems that perhaps there’s nothing to talk about. Of course colors exist in the outside world. Of course my memory is like a video camera. Of course I know the real reasons for my beliefs.

Rather than memory being an accurate video recording of a moment in your life, it is a fragile brain state from a bygone time that must be resurrected for you to remember.

And because the physical stuff is constantly changing, we are too. We’re not fixed. From cradle to grave, we are works in progress.

The same behind-the-scenes work is true of ideas. We take conscious credit for all our ideas, as though we’ve done the hard work in generating them. But in fact, your unconscious brain has been working on those ideas – consolidating memories, trying out new combinations, evaluating the consequences – for hours or months before the idea rises to your awareness and you declare, “I just thought of something!

Listening to Jim’s neural activity – pop!pop!pop! – it’s impossible not to be awed. After all, this is what every decision in the history of our species sounded like. Every marriage proposal, every declaration of war, every leap of the imagination, every mission launched into the unknown, every act of kindness, every lie, every euphoric breakthrough, every decisive moment. It all happened right here, in the darkness of the skull, emerging from patterns of activity in networks of biological cells.

Because of her brain damage, Tammy lacks the ability to integrate her bodily signals into her decision making. So she has no way to rapidly compare the overall value between options, no way to prioritize the dozens of details that she can articulate. That’s why Tammy stays on the sofa much of the time: none of the choices in front of her carry any particular emotional value. There’s no way to tip one network’s campaign over any other. The debates in her neural parliament continue along in deadlock.

An example of the latter is the postage stamp-sized device called the BrainPort, which works by delivering tiny electrical shocks to the tongue via a small grid that sits on the tongue. A blind subject wears sunglasses with a small camera attached. Camera pixels are converted into electrical pulses on the tongue, which feels something like the fizz of a carbonated drink. Blind people can become quite good at using the BrainPort, navigating obstacle courses or throwing a ball into a basket. One blind athlete, Erik Weihenmayer, uses the BrainPort to rock climb, assessing the position of crags and crevices from the patterns on his tongue. If it sounds crazy to “see” through your tongue, just keep in mind that seeing is never anything but electrical signals streaming into the darkness of your skull. Normally this happens via the optic nerves, but there’s no reason the information can’t stream in via other nerves instead. As sensory substitution demonstrates, the brain takes whatever data comes in and figures out what it can make of it.

But it’s clear that we are no longer a natural species that has to wait for sensory adaptations on an evolutionary timescale. As we move into the future, we will increasingly design our own sensory portals on the world. We will wire ourselves into an expanded sensory reality.

what if there is nothing special about biological neurons themselves, and instead it’s only how they communicate that makes a person who they are?

how does something as rich as the subjective feeling of being me – the sting of pain, the redness of red, the taste of grapefruit – arise from billions of simple brain cells running through their operations? After all, each brain cell is just a cell, following local rules, running its basic operations. By itself, it can’t do much. So how do billions of these add up to the subjective experience of being me?

Like an ant, an individual brain cell just runs its local program its whole life, carrying electrical signals along its membrane, spitting out neurotransmitters when the time comes for it, and being spat upon by the neurotransmission of other cells. That’s it. It lives in darkness. Each neuron spends its life embedded in a network of other cells, simply responding to signals. It doesn’t know if it’s involved in moving your eyes to read Shakespeare, or moving your hands to play Beethoven. It doesn’t know about you. Although your goals, intentions, and abilities are completely dependent on the existence of these little neurons, they live on a smaller scale, with no awareness of the thing they have come together to build. But get enough of these basic brain cells together, interacting in the right ways, and the mind emerges.

After all, a city is built on the interactions between elements. Think of all the signals moving through a city: telephone wires, fiber optic lines, sewers carrying waste, every handshake between humans, every traffic light, and so on. The scale of interaction in a city is on a par with the human brain. Of course, it would be very hard to know if a city were conscious. How could it tell us? How could we ask it?