En Memoriam

…how easy for us to believe in a single, concentrated cause for complexity, and how hard to find visceral satisfaction in the accretion of infinitesimal influence that is more often nature’s way.

–T. Lewis, F. Amini, and R. Lannon, A General Theory of Love

Memories have no bones or eyelashes. They are not objects in the same way that belt buckles and tree stumps and finch feathers are. They cannot be held like prisoners or evaded like authorities. And though I like to imagine I can marshal my own, memories are biologically unreliable and behaviorally inconsistent.

As I stand on this basaltic mountain and look down the sloping green hillsides to the Atlantic Ocean, I will my mind to remember every detail of the experience. I take a quick burst of twenty digital pictures of everything I can see. I try to imprint the smells, the sounds, the way the sun feels different as it hits the Canary Islands, thirteen degrees closer to the equator than my current home in Wyoming. I’m supposed to be listening: a Spanish ecologist is giving a lecture on the anthropogenic impacts upon Europe’s most diverse biogeography, but instead I’m staring down a small sparrow-like bird. It darts through the juniper bushes too quickly for a photo, so I want to memorize enough details to identify it later, when I’m back at my desk and field guides.

All day, from the top of Cruz de Taborno Mountain, to the village of Taganana at its feet, I have kept all of my senses on alert with what I hope is permanent tape rolling in the back of my brain. The lecture, the vista, the way the air smells—I don’t want to lose any of it. By the afternoon, this act of trying to record everything starts to feel like a physical exertion. My brain starts to hurt, or I imagine it does. And then the worry begins, that I’ll miss something, that I’m already missing something by over-thinking, that I am not in the moment. Too often, this is how my travel ends up feeling: like a race to record, rather than experience. I look around at the rest of my research group and wonder how they all manage to look so calmly engaged. They don’t look like they have pained brainpans—though it’s likely I’m not the only one.

A memory is an electro-chemical action. It is an event, like lightning, rather than an artifact. After the flash, the lightning itself only exists as an afterimage that wavers, then fades from view, leaving behind a bit of blackened wood or glassed-over sand, the smell of pennies and sulfur.

We understand memories biochemically in two distinct ways: first, as a phenomenon created, and second, as a perception retrieved. For an experience to be recorded by the brain, it must first be sensed by one or more of our eyes, ears, nose, mouth, or skin. These sensory perceptions are encoded in chemical signatures and carried by specialized nerve pathways to our cortex, then stored in synaptic neurons. For many years, neurobiologists have relied on the analogy of computer memory to describe what happens in our much more chaotic and soupy internal ecosystems. For example, a computer translates information into binary code and then stores it with address markers that will enable faster retrieval. However, the human brain doesn’t generally store information the way a computer does. The human brain stores meanings: a string of numbers—0529—in a computer is data; but in my (and my mother’s) brain, it is my birthday. Though two computers would store and recall the numbers identically, both my mother and I not only have different meanings associated with those numbers, they are attached to different experiences (or markers) as well. I may think about birthday cakes and parties I’ve had, while she may remember what I smelled like on that first day, how her body ached, the paint on the delivery room walls. Humans require a code much more complex than...