By Randy Jackson—

Beyond a certain age, it becomes strikingly clear how much our memories define who we are, or who we think we are. What we remember, whether true or false, ends up defining us. Memory is a complex and fascinating faculty, and understanding even a few of its features helps us better understand how we make sense of the world.

If you can imagine awakening from a deep blackout sleep, one in which your brain needs to reboot, you would have three profound questions: Where am I? Who am I? And who (the hell) are you? At that moment, you really need your memory to perform three different functions. These three functions are handled differently with varying degrees of accuracy and reliability within your cranial complex. These are: Geographical Memory to know where you are. Autobiographical Memory to recall who you are. And Facial Memory to recognize others.

Geographical Memory

As a seasonal resident, sometimes waking on the first morning in Huatulco results in a brief but sudden shift in orientation. That felt shift seems to be the result of my brain recognizing the familiar bedroom surroundings of our place in Huatulco, while realizing I’m not in Calgary anymore. And although I’m sure no neurologist would ever describe it this way, it seems like the geographical memory snapped into place.

In fact, our geographical memory function is one of the oldest and most developed in evolutionary terms. Well before we had language ability and could formulate abstract thought, we could remember where we were. John O’Keefe, a brain researcher, discovered, in the 1970s, what he called “place cells”: brain cells that fired only when an animal stood in one particular place, and nowhere else. In 2014, this work won the Nobel Prize after further discoveries showed that brain cells formed a hexagonal map of any space we move through. So who knew, that first-morning surprise awakening in Huatulco is backed by solid brain science.

The capacity of our geographical memory is perhaps best demonstrated by research on London cab drivers. What cabbies call ‘The Knowledge’ requires them to memorize an extraordinary amount about London’s notoriously complex network of roads, place names and landmarks. I can vouch for this ability. Once (before Google Maps), after getting off at the wrong underground stop and being hopelessly lost, we took a bus to who-knows-where, hoping to find a place to catch a cab. Then, getting off at a random bus stop, we found a London cab that recognized the street name our hotel was on. Saved by the enlarged hippocampus of a taxi driver. Brain scans have shown that London cabbies have a larger-than-normal area of the brain most tied to spatial memory.

Autobiographical Memory

That impressive ability of humans, and no doubt other animals, to know where we are does not translate so well to remembering who we are. Autobiographical memory is notoriously poor, or perhaps better said: “flexible”. But “flexible” enough to clearly remember things that never happened.

Often cited as an important “where were you when” example is the account of people remembering where they were when they first heard that John F Kennedy was assassinated. It’s a term psychologists call Flashbulb Memory. The idea is that the emotional impact of hearing of a tragic event cements the details of where they were when they heard the news. But when psychologists have actually tested such memories, they’ve found otherwise.

The day after the Challenger Space Shuttle disaster, in January 1986, researchers asked a group of students to write down where they were and what they were doing when they heard the news. Three years later, they asked the same students again. The students were confident in their memories, but often those later memories were wrong. Even when shown their own handwritten account from the day after, some refused to believe it, trusting their most vivid current memory over the document in their own hands.

Getting some details wrong about a past event is one thing. Remembering a whole event that never happened is something else. This may be best demonstrated by a 1995 study titled “Lost in the Mall.” Researchers first interviewed each subject’s family members to gather three real events from that person’s childhood. Then they presented those three, along with a fourth, a made-up story about being lost in a mall as a child but rescued unharmed by a kind stranger.

Over two interviews, they asked what the subjects remembered about each event. By the second interview, about a quarter of them not only “recalled” the mall incident that never happened but had begun to furnish it with details of their own, such as what the kind rescuer was wearing.

And if getting details wrong over time and remembering things that never happened aren’t bad enough, another fly in the ointment of autobiographical memory is how our brains reconstruct our memories. It is a misconception to think our brains are like computer memory, where the data stored is the same data recalled. Rather, each time we recall an event, we rebuild it, filling gaps from previous versions and coloring the result with the mood and circumstances of the moment. Then this revised version of the memory is stored until the next recall, creating a slow drift over time.

Facial Memory

As unreliable as our autobiographical memory can be, we are very good at remembering other people — not their names, of course, or even where we might have seen them before, but in recognizing the face itself. In fact, some people show exceptional skill in this ability.

At the time of the London riots in 2011, Constable Gary Collins of the London Metropolitan Police was on vacation. Recognizing some of the faces in the television news coverage, he returned to work to help identify rioters in the grainy CCTV footage. Collins identified around 180 suspects from riot imagery. The Met’s facial-recognition software of the time identified just one. His unusual ability helped prompt the Met to establish a dedicated super-recognizer unit, built on the small number of people who possess a supersized portion of our ability to recognize faces.

The three questions I opened with: Where am I? Who am I? Who are you? are each answered by a different memory faculty. Our sense of identity leans on all their answers. To demonstrate the importance of these memory functions, we might look to an example of someone who can no longer answer any of the three correctly.

In the essay ‘A Matter of Identity’, neurologist Oliver Sacks describes a patient of his, William Thompson, who has Korsakoff’s syndrome (the alcohol-related memory collapse). When Thompson was alone, out in the home’s garden, he sat quietly. But the moment another person appeared, a face he could not place, the confabulation ignited. He would take the stranger for someone he knew, then improvise a time and place to fit, often articulate, often interesting, a whole new identity assembled on the spot.

Thankfully, unlike Thompson, we do not invent a new self for every stranger we meet. Perhaps the brief disorientation we sometimes feel on waking is a reminder that our sense of self depends not on memory being perfectly accurate, but on it being flexible enough to bend without breaking—and still carry one continuous self from one day into the next.

Randy Jackson blends local reporting from the perspective of a seasonal Huatulco resident with explorations of life and change in Huatulco, Oaxaca, and Mexico. Email: box95jackson@gmail.com