Memories of a Mugging.
Memory is built by different sensory modalities but misled by those same senses. Memory explodes the myth of separate senses. When a young boy sees a backwards six, and says--that's wrong, it's too orange, six is redder--he is living the blurred boundaries of evolutionary history.
We are layers of history, our evolved selves, not fully traceable through species trees, because while species change and split all the time, traits do so even more messily. Traits may disappear from a lineage, only to reappear later, when selective pressures toggle a cascade of developmental switches--stick insects lost wings as they became twig mimics, but some have since regained wings, and the ability to fly. Those wings were buried deep. Or traits may simply appear, with no common history, in distantly related parts of the tree of life--neurotoxins in poison frogs and pitohui birds, syntax in parrots and people. Traits reticulate, and converge.
Our ancient animal ancestors had a tripartite brain with the same three primary divisions that persist in all vertebrates today. In early fishes, those brain divisions--fore, mid, and hind--were loosely associated with smell, vision, and hearing, respectively. But selection acts in original ways, and as different senses have risen to prominence over time, where brains do what has moved around rather a lot.
In mammals, the cerebral hemispheres, part of the forebrain, have grown relative to other parts of the brain. With that increase in size of the primitively olfactory forebrain, the Age of Mammals became, de facto, the Age of Smell. To put it more precisely, the Age of Chemical Senses, but smell is a good stand-in for all of them, the most well-known of the others being aspects of taste. Watch your dog map the world by scent, or your cat pull olfactory information out of the air with his mouth slightly open, and be assured that other mammals rely strongly on smell. In those same expanding forebrains, we mammals were integrating olfaction with memory, and developing the corpus callosum, a powerful band of fibers that connects the two halves of our increasingly complex and asymmetric cerebral hemispheres. Mammals increase communication and connectivity in myriad ways--and we often do so through smell.
A small group of rogue mammals emerged some time ago with opposable thumbs, small snouts, and large eyes oriented to the fronts of our heads, however, and we primates, particularly the monkeys and apes, came to prioritize vision over smell. Those forward-facing eyes gave us binocular vision, and thus depth perception, but our big and growing forebrains were already dominant, so visual processing took over some of the neurological real estate that, long ago, was primarily the domain of smell.
Then we became human, spoken language arrived, and audition rose in the ranks of senses. Language processing showed up in the forebrain alongside visual processing, as well as pretty much all the other cognitive functions that contribute to making humans dominant on Earth--analysis, creativity, emotion, math, consciousness. All sitting in a prehistorically smell-focused area of the brain.
I was in Ecuador with twenty undergraduates, about to lead them in a six-week biological expedition around the country. We had known each other for months back on campus in the States, but this was day one of the trip. Not even--I had arrived late the night before, and most of my students had arrived a few days before me. The trip officially started the next day. It was day zero.
Planning to wander Quito alone that Sunday, I was happy to have three of my students join me. We headed vaguely towards "old town," following a few short flights of stairs en route. Stairs in foreign cities are intriguing; they often go places you can't know. In particular, old stone stairways are an invitation. Individual creations all, sometimes they're co-opted for a new destination, sometimes they dead-end at a wall. I tend to follow them when I see them.
Quito is long and thin, sprawling linearly in both directions from the old colonial center at its heart. One of the city's boundaries is the Pichincha volcano, which has, of late, been spreading ash over the city every few years. On this day in early February, the 60-degree weather felt warm to us, newly arrived from the North, and we explored all day, slowly getting acclimated. By four, we were talking about heading back to the hostel, when we saw the most enticing flight of stairs yet.
It was twenty feet wide at the bottom, grand steep flights plateauing every thirty stairs or so before climbing again, the stairs visibly narrowing as they disappeared from view.
We began climbing, stopping to admire the view of the Virgin, the tall winged statue visible from many points in the city, or to catch our breath. At every plateau, a new vantage. Short stone walls on both sides blocked views into ramshackle residences, a school. It was quiet and still--no people at all, except for one man who passed us near the top. I said "buenos" to him, short for buenos dias, a friendly, humanizing gesture that is nearly always reciprocated by strangers in Latin America. He looked at us and continued on without words. Shortly thereafter, we viewed a street ahead and decided to turn there and head North, towards our temporary home.
Out of nowhere, two men, one flashing a long knife, run up to us. The one holding the knife, straight out of Hollywood in a dark hoodie with two long scars across his face, approaches Michelle. She is our photographer, and has both a backpack and a nice DSLR camera around her neck. The other man runs up to Jeremy and gestures for him to hand over his bag. Jeremy is far bigger and stronger than the guy on him, and he has a knife of his own in his pocket, but Scarface has his knife too close to Michelle for Jeremy to do anything but hand over his bag. I have nothing on me--nothing obvious, some cash and id flat in my pocket--nor does Arthur, and I stand, back towards the wall, hands out, palms up, watching. Arthur, with martial arts training, has adopted a similar pose across the way--non-threatening, docile--and we will learn later that he has his eye trained on a large dog that is at risk of joining the fray. I do not see the dog.
Scarface in the hoodie stands so as to keep Michelle and me against the wall, and he takes his long fixed-blade knife and crouches, swaying, scraping his knife blade against the cobblestones in broad arcs, glittering eyes trained on us. It's a crazy low knife dance around Michelle, and is riveting. Then he stands and has his knife above her shoulder, making stabbing motions. My brain keeps suggesting that this is a joke, some sort of play. Not that it's not really happening, but that it's theatre. Then Michelle is lifting her camera off her neck--oh, it goes so slowly--and removing her backpack. I feel calm.
Sensory memory is the shortest-term of the memories, and is divided lyrically: Echoic refers to the memory of the just heard, iconic to the just seen. Anything we are conscious of has likely moved from sensory memory into proper short-term memory, though we continue to encode it in sensory terms.
We trust some senses more than others. While somewhat variable between people, in general we privilege sight. A first-hand account of an event in which the action was heard, but not seen, seems less legitimate, and even less likely to be true, than a firsthand account of an event told by someone who saw the whole thing. The ear-witness has less credibility than the eye-witness. Smell-witnesses are character actors--specialists, if you prefer. Smells, as Proust intuited, are best at triggering detailed, emotional memories. Smells are also especially likely to return us to our earliest days, our first decade of life, moments we may have had no access to until the key of olfaction--gingerbread, jasmine--unlocked them.
Our sensory modalities usually take in redundant data, assuming situation normal. The redundancy is not wasteful--selection would have weeded out such expensive waste long ago--but protective. The physical characteristics required to transmit signal through each modality varies, rendering each strongest under different circumstances. Sound can travel a very long distance, even in the dark, but can be difficult to localize--to identify the source--especially as distance from that source increases. A visual cue is highly localizable--you know where it is, but only if there's light. Touch, itself an amalgam of many inputs, requires that you be right next door. Aroma needs a current of air or water to travel on, and the signal itself can't change very quickly. You may have long ago heard the bacon sizzle in the pan, seen it hit your plate, and felt the fat and crunch in your mouth, but, unless you open the windows and welcome in a strong wind, your house will smell of it for a while to come.
Sometimes you know that one of your senses is weakened--stuffed sinuses reduce your ability to smell, impending night shuts off color vision. In situation normal, though, you might assume that you are walking around the world seeing, hearing, smelling, tasting, feeling--everything. Call on an event in your life as you read this, though, some event both notable and very recent, and try to determine the nature of all of the sensory inputs. In all likelihood, you can infer from context and history what your daughter's soccer game looked like before play began, what the theater smelled like at the end of the movie, what sunset on the beach sounded like. But inference is not the same as memory. You probably did not actually upload those less primary sensory modalities as part of the memory, instead borrowing what you know is usually true, and plugging it in to the appropriate place in the story. After the fact, you remember the constructed and hybrid narrative, and likely don't have access to what you actually know from that moment in time.
What happens when the story goes wildly off track? What of entirely new experiences, or obviously dangerous or traumatic ones? On the street in Quito, I came to on the second guy, hands gripping his shoulders, pulling on the backpack he had stolen from Jeremy. (Jeremy, meanwhile, had given chase to Scarface.) I don't remember beginning to run after him, nor deciding to run. I don't remember not remembering. But I have visual memories of watching Scarface take Michelle's gear, while he held a knife to her; and I have a visceral-intellectual memory of thinking, at that moment: no. We were at the top of the wide stone stairs, and then--I was on the other guy, mid-street. I was there and now it was loud and bright and chaotic, and not just because everyone was yelling and running, an entire neighborhood had appeared where before there had been no one, and the police improbably chose now to spring into action from god knows where, their wheels spinning on the cobblestones, sirens dopplering up from behind me. This was all noticeable not just because the experience was so very unusual, but also because, I realized with a shock, my memory of what came immediately before had no sound associated with it. And no color.
Did touch bring me back to full sensory awareness? I don't remember running at him, but run I did, by the evidence, and the accounts of others who were there. Being on him, tugging on him, inputting one more sense into the scene, may have triggered my attention back to full sensory. Or perhaps it was that we had won. Crisis was still mid-swing, to be sure, but nobody had been stabbed, and it looked like we were even getting our gear back. Jeremy had caught up with Scarface, who had given up all his stolen loot as well, dropped his knife in the street, and run.
We do not have the processing power to take everything in, interpret it, and store it. We need editors to distinguish between all that might be perceived and all that is perceived; between what is perceived, and what will be remembered short-term; between that and what ought to be remembered long-term. Also, in the role of file clerk, we need decisions made about which experiences are sufficiently regular and repeating such that new versions only rarely need updating, and which are sufficiently unique to be remembered as distinct experiences.
We are always editing. Attempts to become fully conscious of our bodies, and attentive to everything around us, promoted by myriad traditions throughout the world, will indeed provide a sense of greater time. And wouldn't it be nice to see, feel, smell, hear everything at all times, to never miss the gorilla on the basketball court. But is it a good idea to try to override our internal editors? True, they make us subjectively blind, make decisions for us regarding what to attend to. But those editors, at least some version of them--be they sensory, linguistic, or some other cognitive wizard--are necessary if we are to wander the world in anything but a haze of total bombardment.
From an evolutionary perspective, the same idea, of selective attention to some and not other signals on a particular channel, must apply between the senses as well. In the moment of emergency, when you cannot know what among all the possible inputs will prove to be important, all systems are go. The fact of information being input across all channels--because less is being assumed about background reality, and because old data has a good chance of being bad data--explains the sense of time slowing down. Normally you can't perceive and experience this much in five minutes, so it feels like longer. Furthermore, the brain goes back and retrieves some things that just happened, which otherwise would have disappeared after a few minutes, and holds on to them, just in case. Were you paying more attention to your world just before disaster struck? In some cases, sure, but generally no--most disasters provide no warning. Therefore, your brain must constantly be uploading the banal experiences of daily life, and discarding them after a time, you none the wiser, at least not consciously. Twenty years of research points to just that.
We are the most plastic of animals, in terms of responding to new and unexpected inputs, and our brains show similar plasticity. We can deal with evolutionary novel situations--like looking at cake while tasting sour vitamin C--and still know that cake is sweet, although it takes slightly longer for us to know so than when the sour gustatory input is absent. We each have dominant cognitive styles--visual or verbal--and a visually-oriented brain not only processes pictures faster than words, but it converts words into pictures and then shunts the processing into the visual part of the brain. And we co-opt brain space when one sense goes off-line for a long time: some blind people echolocate to map the space around them and, at least sometimes, they use the visual parts of their brains to do so.
We can act like synesthetes in moments of stress, confusing and conflating what information came in on what channel, remembering a sound when perhaps we only had a quick visual flash. Sensory modalities directly influence each other when they can. It is known that the presence of a signal in one modality--hearing--improves the ability to detect a visual cue; the same should hold true across other senses as well. It would have to, wouldn't it--none of us are unisensory beings, and the different modalities must be integrated, drawn on a similar enough map that they can communicate with one another. This crossmodal construction of space happens with no awareness on our part, and the formulation of our stories about how we know what we know, and indeed merely what we claim to know, are therefore suspect. Even eye-witnesses are sometimes wrong.
What then, to make of the fact that my memory of the mugging includes no sound or color? Afterwards, we were four participants in a shared event who had coincident, but all differently incomplete, memories of the event. Jeremy also remembered no color. Michelle didn't know the knife had been at her shoulder. Arthur had been focused on the large dog sprawled at the top of the stairs, and his attention may have kept one or more of us from getting attacked by it as well. Everyone else heard that dog barking throughout the interaction, but me, I was surprised to learn that there had been a dog. Later that evening, at the hostel, after we had tried to secure our actual memories in place before sharing with the rest of the class, Arthur told the part when Scarface scraped his knife menacingly on the cobble-stones. Arthur acted it out, making the chhh-chhh sounds vocally. I interpreted him literally, though, and thought that Scarface, too, had made the sounds with his mouth.
Now, though, the sound has ensconced itself so fully in my narrative that I cannot envision the knife dance without also knowing the sound. In many situations, sound has less meaning for me than does sight or kinesthetic experience. Development, and perhaps heredity, created these strengths, and concomitant weaknesses. In the trade-offs themselves come adaptations. Time slowed, lines were crisp at the center, fuzzy outside of the focus, and I don't remember color. My brain focused and edited at the same time. I watched, and then I acted. Sensory modalities may go off-line in times of acute stress, and whatever I heard, it did not make the cut, so I filled sounds in later from the more attentive ear-witnesses.
A complete explanation of what happened to each of us required a collective sharing, each of our blind spots, metaphorical and otherwise, filled in by the others. Having been mugged, then speaking of it, writing it, acting it out--we were translating memories through different modalities, and in so doing, both altering, and solidifying.
What grabs our attention? What do our internal editors let through, and give us access to? Novelty, perhaps--you stop noticing your new sofa after a while, until you move it, or stain it, or something of note happens on it. But novelty only keeps our attention, gets past those editors into stored memory, when it breaks expectations in some way. Novel events are only noticed when they don't fit with our already constructed models of the world. And if we have no model at all, new information may simply not be noticed--the spaceship on the cricket pitch is too unreasonable, it must be somebody else's problem. Put another way, you have to have enough information in advance to know that an event is novel.
If you aren't attentive to when plants flower, when the huckleberries outside your window bloom earlier than they usually do, you won't notice, even though the information is there to be had, and it is new. A botanist or gardener, however, with a vested interest in the timing of such things--or any careful observer of nature-will take note. The more certain we are of our understanding of a situation, the more likely we are to throw out new, discordant data--often at our peril. And the naiver we are, the less likely we take in data about it at all. In that vast in-between space--having some experience, having a model, but being open to the modification of that model--that is where perceptions take hold, and learning begins.
At the mugging, I had internalized the unfriendly man who passed us moments before, but he hadn't registered for the others. His failure to play by usual rules in this setting--I say hello to you, you say hello back, or at least nod pleasantly--had been notable to me. I knew the rules, but my students were new to Latin America, so they didn't have a model of what to expect. He was the only other human on our entire climb up the stairs, so they must have seen him at the time, but their brains had thrown it out as useless information shortly after the fact. Later, I interpreted him as an associate of the two who attacked us--there was evidence of Scarface texting unknown others, and the unfriendly man had reversed course to stand in the shadows later, when the two attackers had been chased down again, this time by the police, and brought to us for identification. He was watching the scene quietly, while the rest of the neighborhood had broken out into a block party, with music, people hanging over balconies, old women coming up to congratulate us for fighting back, and to tell us that these two had been trouble in the neighborhood for a while now. Or perhaps I am misremembering the music.
How do we predict the future--when the sun will rise, how long it will take to get across town, whether our friend will prove good to her word? We use past knowledge, stored in memory, to construct plausible scenarios which, when proven wrong, we modify. It should not be surprising, then, if the mechanisms of remembering the past are similar to those of imagining the future.
In the middle of the block party, Scarface texted while spread-eagled against a cop car, and the neighborhood applauded us. After that, things got harder to predict. Having been encouraged by the police at the scene to make a statement, we were taken to a tiny one-room police station, then badgered by the cops there not to make a statement. Scarface's sister, baby on her hip, came in crying, pleading for mercy for her brother. Perhaps, these new cops suggested, my friends could be taken to the hostel and I could be conveyed to a different station, where it would be possible to make a different kind of statement? No. Ah, well, a statement here, in this station, certainly couldn't be done today--perhaps next week? By then we would be long gone, deep in the Amazon. Ultimately, we demanded only one last face-to-face with our attackers; we saw nothing but satisfaction in Scarface, but his associate had remorse in his eyes.
We were offered a ride back to our hostel, and what a ride it was. Stuffed four across into the back seat of a pick-up truck, the sirens blared, and a motorcycle cop escorted our truck through rush-hour Quito. Whenever we were jammed up in traffic, people in adjacent cars averted their eyes, or glanced quickly at us to see what bad gringos looked like. Arthur started cheerfully waving out the window at people, and one mother covered her child's eyes to protect the little one. My body felt fizzy, and everything I saw was both hazy, and in sharp relief. And then I started laughing, not loudly, but laughing. It was all too much.
What is evoked for you by the sweet sharp tang of cumin; the flitting chip-chip of a hummingbird; soft elementary school paper, red-and-blue-lined newsprint flimsy in the hands? Warm rust and your father's chili; the return of Spring; the careful, agonizing scrawl of being seven years old? Deja vu, yes, but also deja entendu, deja senti, and therefore deja connu. We know so much of what we think we know on the basis of direct sensory experience. A splash of royal blue, notes played on a mandolin, the smell of low tide--how much is required to take us spiraling back to a moment we have not thought of in years, perhaps did not know we knew?
The four of us had many opportunities to shape and mold new memories from what we collectively agreed on that day. We did less of that than you might imagine, since starting immediately afterwards, on day one, I had a whirlwind of other experiences planned, so retelling this story dropped faster on the do tell list than it would have in other situations. I had had this sensation of being engaged, unwittingly, in theatre, when it was happening. Afterwards, Arthur interpreted it thus: We were all playing parts. Scarface had the knife, and the intent to rob; our collective role was to observe, and wait for opportunity. Which we did. As soon as our attackers had turned their backs to us, run away and separated, our roles changed.
How did we know our roles, though? Each of us had enough relevant experience, both direct and indirect, that we had a model. We had enough shared time together--in life, many months, and that day, many hours of shared exploration through a city relatively new to all of us--to trust each other to make good decisions. It's hard to go back and reconstruct what senses might have gone off-line for the others, but even if each of us had a major sense shift or shutter, there was back-up, because we were a unit, and we had each other's backs. Each of our individual senses pulled a selective attention edit on us, and so we all forgot some things on every channel. And within each of us, it is almost certain that some senses got left in the dust by the ones that were better able to take in crucial information as it arrived. But we were that most human of things, the social group with both shared history and shared fate. And that truth--along with some initial conditions that worked in our favor--got us through.