I regret that, in telling the story of that night over the years, I have destroyed countless people’s peaceful relationships with their toilets. I know this because they say so (“Becca, I think of you every time I go to the bathroom!”), before fishing for reassurance that such a catastrophe could never befall them. Sadly, I can’t provide it, since the cause of the explosion remains unknown. I can only offer my annoyingly incomplete hypothesis, based on some Google bingeing and the best guess of a plumber’s son I met at a party, that it involved excess air pressure in the system that flushed the building’s toilets from a giant water tank in the basement. So if your toilet is flushed by water from its own little commode-top tank, you can probably exhale now.
What I do know is that my injury posed an existential threat. If I hadn’t acted as I did, I might have bled to death, or lost enough blood to suffer permanent damage to my brain and other vital organs. Nobody would have come looking for me in time to prevent any of that. My neighbors, conditioned to ignore mysterious, big-city noises, slept through the brief blast. Colleagues and friends would have assumed they’d missed some explanatory email from me when I failed to show up for that Friday workday or a weekend meal, and my family wouldn’t have expected to hear from me for days. For all anyone knows, then, I saved my own life. Or at the least, life as I knew and wanted it to be.
People admire me for this feat. I admire me for this feat. I’ve inwardly gloated about it in infuriating or demoralizing situations, like when I had to sit with my “feedback is a gift” face on for fifteen minutes while a boss explained that I am not a creative thinker (I disagree). Ah, so that’s what you think of me? No matter. I’ve saved my own life. But while the admiration feels good, it also discomfits, and not only because so many people dislike women who own their achievements. More so because it implicitly credits me with consciously orchestrating every step of my escape from danger, ignoring the extensive role of factors beyond my control—beginning with the brain’s built-in threat-defense program.
Nerve cells, or neurons, play a starring role in the threat-defense program. Neurons’ raison d’être is to relay data, in the form of electrochemical transmissions, throughout the brain and body. While they take slightly different forms depending on their location and purpose, you can imagine their fundamental anatomy as that of a dandelion gone to seed: there’s a cell body (dandelion head) covered in dendrites (the fluff on the head) and a skinny, stemlike projection from the cell body called an axon, which has branches at its end, like roots. (This is an imperfect analogy, as dendrites are actually thicker than axons, but it’s good enough for our purposes.) The structures we call nerves are actually bundles of axons.
When adjacent neurons communicate, one neuron generates an electrical impulse that travels from the top of its axon through to its branching ends. There, the impulse stimulates the release of chemicals, which diffuse across a tiny, fluid-filled gap to react with the dendrites of neighboring neurons. Reactions above a certain threshold cause those neighboring neurons to generate their own electrical impulses, leading to stimulation of other neurons in their vicinity, and so on. Such communication transpires on an unfathomably large scale. Estimates peg the number of neurons in the human nervous system at around 100 billion, and a single neuron typically communicates with ten thousand others. The result is trillions of neuron-to-neuron connections. If we could hear it, the chatter among them would be deafening.
Neurons are the workhorses of the central nervous system (which comprises the brain and spinal cord) and of the peripheral nervous system (the network of nerves that permeates the skin, muscles, and organs). Communicating via neurons, the central and peripheral nervous systems form a feedback loop that enables collection and processing of data about the body’s internal and external environment, and coordination of the body’s responses to it, whether automatic or consciously deliberated.
Within the brain, different groups of neurons—neural neighborhoods, if you will—specialize in processing particular types of data, for instance that related to visual stimuli. And specific neural neighborhoods routinely collaborate to carry out specific processing tasks, like the threat-defense program.
How did all this work to my advantage? At the instant of the explosion, several neural neighborhoods involved in the threat-defense program leapt to work, crunching data about the sights, sounds, and bodily impact of the event to synthesize a detailed account of it. One of them—the amygdala—also compared rudimentary facts about the event to situations tagged “dangerous” in my evolutionary programming and memory. Discovering troubling similarities, it triggered a full-body response to help me cope with the danger I faced.
Muscles all over my body contracted, freezing me in readiness to assume whatever posture the situation demanded next. Natural opioids flowed into my spinal cord, blocking pain-triggering sensory nerve signals en route to the brain for processing. My breathing quickened and adrenaline flowed into my bloodstream, boosting supplies of blood glucose—muscles’ main source of energy. My heart pumped faster to speed distribution of the surplus energy throughout my body, and blood vessels channeled it into my limbs (where it would likely be needed most) by constricting themselves in my abdomen and skin, and relaxing in my arms and legs.
Body thus poised and fueled, a cascade of chemical reactions in my brain whipped up its processing rigor, and the whole organ kicked into a state of high alert, consumed by the work of monitoring the situation and sustaining my physical preparedness. Fear—thought to occur when the bodily symptoms of this state bubble into consciousness—failed to transpire.
Within milliseconds of the blast, the threat-defense program had transformed me from a groggy corporate climber into a hypervigilant animal, hell-bent on survival and primed for action. But what action? The threat-defense program can automatically initiate a handful of survival strategies that have proven helpful throughout human history, famously including freezing, fleeing, and fighting (negotiations with bloodthirsty predators, I gather, routinely fall apart). It can also initiate strategies that an individual has learned, like the battlefield injury-management protocols that soldiers internalize through extensive drilling. Such stock strategies are fast, and effective to a point . . . then one needs to address the particulars of a situation.
That’s when the cerebral cortex—the wormy outer layer of the brain, which specializes in tough processing jobs—jumps in to bang out a bespoke survival strategy. I experienced the process as a lightning round of straightforward decision-making: Wait for help, or take action? Stop the bleeding first, or call 911 first? Bind the wound with a terry-cloth bathroom towel or a linen dish towel? End to end, however, contemporary science suggests it was much more complex.
At every decision point, my cortex drew on processing capacity and information throughout the brain to define a range of possible actions. Then it assessed and ranked each according to potential survival benefit, identified the best bet, and commanded my body to carry it out. Concurrently, processing loops strengthened by the threat-defense program provided my cortex with granular feedback about the impact of each action taken, for incorporation into the developing strategy.
Neuroscientists don’t fully understand how the cortex manages all this. But many agree that several mutually influential human assets play a critical role. One of these is language, which, as asserted by contemporary philosopher Daniel Dennett, “lays down tracks on which thoughts can travel.” For instance, with the pronouns I and me, language gives us the concept of a self—an entity that acts and is acted upon—and with verb tenses, it gives us the concepts of past, present, and future, thus the possibility of a self that persists over time. Other assets crucial to planning include the type of consciousness that makes us aware of, and able to reflect upon, our selves and our experience (versus simply being awake), and our capacity for storing and recalling facts and personal history in memory.
Interacting in innumerable ways, language, consciousness, and memory allow us to recognize both physical and conceptual phenomena that concern us. They enable us to construct multistep plans for addressing the problems and opportunities we face, and to apply knowledge we’ve acquired about our selves and the world in doing so. And they endow us with the superpower of mental time travel, so that we can project our selves into the future to explore the potential consequences of those plans.
I had the sense of deliberately leveraging these assets during my escape. Wait for help, or act to save myself? Knowing I lived alone, and that blood loss can lead to death, I imagined waiting for help. I saw myself slumped dead against the inside of my apartment door—a blurry mash-up of dark-green paint, pale limbs, and a blood-soaked purple silk chemise—and knew I had to act. Stop the bleeding first, or call 911 first? Knowing I’d never dealt with a gushing wound before, I saw myself trying, failing, and heaped against the door again, no help on the way. I called 911 first. And so on, with each dilemma that sprang to mind, until I finally delivered myself into the care of my horrified neighbors.
I wish I could explain that sense of deliberate decision-making in terms of the cortex’s operations (cue empathetic belly laugh from neuroscientists and philosophers everywhere). But the precise means by which conscious experience arises and influences nonconscious brain activity is the subject of many vigorously debated theories, rather than scientific fact. So, I can’t explain. And that’s fine, because in studying and pondering the subject, I’ve concluded that whatever my conscious contribution to my survival that night, that’s not what’s admirable in the story.
What’s admirable is the capacity nature has endowed humanity with to confront novel, life-threatening events with time-tested survival strategies, and the creativity to improvise new ones on the spot. We needn’t be privileged to possess it, or extraordinary to leverage it. Ubiquitous and renewable, it’s available from an early age, and automatically activated as often as necessary. It doesn’t guarantee survival, of course; we are mortal, after all. But like gods bursting onto the scene of a Greek drama, it can deliver us from the most seemingly hopeless scenarios. And in this one, it gave me a second life.