Adventures in Memory. Hilde østby

When Julius Caesar Arantius named it the hippocampus, it probably was not solely due to its appearance. Seahorses, like silkworms, were special and somewhat mysterious during the Italian Renaissance. When an event is special and unique, it helps the hippocampus hold on to it as a memory. We know that now, but Arantius could not have known that about the tiny part of the brain he had discovered. He just wanted his discovery to be noticed—and remembered.

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       DIVING FOR SEAHORSES IN FEBRUARY

       Or: Where do the memories go?

      Memories have huge staying power, but like dreams, they thrive in the dark, surviving for decades in the deep waters of our minds like shipwrecks on the sea bed. Hauling them into the daylight can be risky.

       J.G. BALLARD, “Look Back at Empire,”

       The Guardian, March 4, 2006

      BEYOND THE PIER at Gylte Diving Center, an hour’s drive out of Oslo, Norway, there are more than forty different types of marine slugs (nudibranchs). They come in all colors, from dark purple to transparent white. Their bodies are covered with tentacles with small stars at the tip, or are decorated with pink fringes like a Disney character from the 1950s. They stretch orange fingertips toward the shiny ceiling of the water’s surface or defiantly pull their luminescent, light-green feelers into their bodies. They slither around in clouds of glittery particles that swirl around the water here by the pier.

      The water is only forty degrees Fahrenheit. Farther into the fjord, we’ve seen ice floes bobbing up and down at the water’s edge. Soon, the slugs in the water will be joined by ten black-clad men chasing the seahorse’s secret. The divers’ flippers thump against the pier as they hobble like penguins toward the sea, then swirl up clouds of particles as the divers slowly sink to a depth of fifty feet. From our vantage point on the pier, we can see bubbles on the dark surface of the water, revealing where the divers are. The seahorses they are looking for are not in the water—we are, after all, in the Oslo Fjord. No, they are hidden beneath their tight diving hoods. The divers have plunged into the ice-cold February water to find out what goes on in the hippocampus. They’re hunting for memory.

      Together we are going to find out how memories behave when they enter our minds. Researching memory is, in a way, quite similar to diving. Our divers are about to break the surface and descend into the depths of memory itself. The only sign that there are memories below the surface is what rises and bursts, like the divers’ bubbles breaking the surface of the water.

      The experiment we are re-creating, famous in memory research, was first conducted in 1975 off the coast of Scotland. Memory researchers Duncan Godden and Alan Baddeley decided to test a popular idea, that you can remember something better when you return to the place where it happened. You know, like in crime novels, where the detective remembers an important detail when he returns to the scene of the crime. It’s a simple theory: when we are in the same environment as we were when an event took place, the memory of it will come streaming back, whether we want it to or not.

      Are memories easier to recall at the location where we first encountered them? How and where do they find a permanent place in our brain? To properly test this, Godden and Baddeley constructed an experiment in which people had to perform a task in two different environments, on land and underwater. Their assignment was to memorize lists of words either on the pier or twenty feet deep in the water, and later recall the lists either on the pier or in the water. One list was to be learned on the pier and recalled on the pier. After some time, a second list was to be learned underwater and recalled on the pier; a third list was learned underwater and recalled underwater; and a fourth list of words was learned on the pier and recalled underwater. The researchers anticipated that everything going on in the water—the cold and wet environment, breathing through masks, and so on—would make the divers remember less than they would on the pier. Theoretically, it should also be harder to learn something underwater as opposed to on land, given that the pressure and the mixture of gases the divers breathe would make it more difficult to focus.

      On this cold February morning in 2016, when we send our divers into the Oslo Fjord, it’s the first time anyone has repeated Baddeley and Godden’s experiment in seawater—some have re-created it in a swimming pool, but we all know that’s not the same. Will these ten men—thirty to fifty-one years of age—show the same results as in the legendary British experiment?

      “Now I can tell you exactly where I have been underwater, after many thousands of dives. I could not do that before,” says hobby diver Tine Kinn Kvamme, the experiment photographer. The lack of oxygen underwater, along with the stressful experience, means that people’s brains function differently from how they usually do.

      “When people first start to dive, few remember anything at all, nor can they report what happened underwater. First-time divers are asked to write their names backward underwater. Often, they will write things like ‘backward,’ or they will turn around only one letter in their name. If you ask them how many wheels a cow has, they’ll answer four,” she says.

      Ordinarily, memories reside within a large brain network. When memories enter our brain, they attach themselves to similar memories: ones from the same environment, or that involve the same feeling, the same music, or the same significant moment in history. Memories seldom swim around without connections, like a lonesome fish. Instead, they are caught in a fishing net full of other memories. When you want to recall a memory, you have a greater chance at catching it if you scoop up the other memories around it. When you pull in the net, it’s full of memories, and you can keep hauling it in until you find the memory you’re after.

      Would memory still work this way in a stressful situation, with subjects who had to deal with diving equipment and other distractions? Would context help the divers remember what they learned underwater when they’re also asked to remember it underwater?

      The experiment in 1975 showed the expected results: the word lists memorized underwater were also better remembered underwater, and the lists memorized on land were better remembered in a dry environment. We anticipate the same from our divers, but we don’t want their expectations to influence the results, so we haven’t told them what happened in the original experiment.

      The atmosphere is tense at Gylte Diving Center. We are not re-creating this classic psychological experiment just for fun: results from psychological experiments are not always reliable. A great deal can happen by coincidence, and it’s often only the results that confirm the hypothesis that are reported, while those researchers who find opposite results tuck them away in a drawer, ashamed and disappointed. When a team of researchers took on the task of re-creating one hundred experiments from different areas of psychology, only thirty-six were successful. The diving experiment was not among the hundred re-creations—but it’s having its time today, an ice-cold and rainy February day in Drøbak.

      Throughout history, philosophers and authors have asked themselves what memory is, how we learn and remember things, and what makes a memory reappear. At risk of offending an entire professional group: in many ways, we can call the philosophers of ancient times neuropsychologists, because they observed and tried to understand how the brain works without having access to today’s research methods. The million-dollar question that everyone is trying to answer is where in our brains our memories actually end up, and how it is possible for all our experiences to consolidate into a pink mass of brain cells and blood vessels. In 350 BCE, in De Memoria et Reminiscentia (On Memory and Reminiscence), Aristotle compared the memory process to making an impression in a wax seal. But exactly how the experiences turned into memories, he couldn’t say.

      By studying the divers at Gylte, we may not be able to see their brains etching words into wax seals, but we can observe how memories connect and become dependent on each other. Context-dependent memory tells us something very basic about how memories are stored. How much you know in a broad sense determines what you understand of the new things you learn. Your understanding of your new experiences depends on your prior experiences. This network of knowledge creates context for the new learnings—they