The Art and Science of Remembering Everything
Without time, there would be no need for a memory. But without a memory, would there be such a thing as time? I don’t mean time in the sense that, say, physicists speak of it; the fourth dimension, the independent variable, the quantity that compresses when yu approach the speed of light I mean psychological time, the tempo at which we experience life’s passage. Time as a mental construct. …
“I’m working on expanding subjective time so that it feels like I live longer,” Ed [Cooke] mumbled to me on the sidewalk outside the Con Ed headquarters, a cigarette dangling from his mouth. “The ide is to avoid that feeling you have when you get to the end of the year and feel like, where the hell did that go?”
“And how are you going to do that?” I asked.
“By remembering more. By providing my life with more chronological landmarks. By making myself more aware of time’s passage.”
I told him that his plan reminded me of Dunbar, the pilot in Joseph Heller’s Catch-22 who reasons that since time flies when you’re having fun, the surest way to slow life’s passage is to make it as boring as possible.
Ed shrugged. “Quite the opposite. The more we pack our lives with memories, the slower time seems to fly.”
Our subjective experience of time is highly variable. We all know that days can pass like weeks and months can feel like years, and that the opposite can be just as true: A month or year can zoom by in what feels like no time at all.
Our lives are structured by our memories of events. Event X happened just before the big Paris vacation. I was doing Y in the first summer after I learned to drive. Z happened the weekend after I landed my first job. We remember events by positioning them in time relative to other events. Just as we accumulate memories of facts by integrating them into a network, we accumulate life experiences by integrating them into a web of other chronological memories. The denser the web, the denser the experience of time.
It’s a point well illustrated by Michel Siffre, a French chronobiologist (he studies the relationship between time and living organisms) who conducted one of the most extraordinary acts of self-experimentation in the history of science. In 1962, Siffre spent two months living in total isolation in a subterranean cave, without access to clock, calendar, or sun. Sleeping and eating only when his body told him to, he sought to discover how the natural rhythms of human life would be affected by living “beyond time.”
Very quickly Siffre’s memory deteriorated. In the dreary darkness, ,his days melded into one another and became one continuous, indistinguishable lob Since there was nobody to talk to, and not much to do there was nothing novel to impress itself upon his memory. There were not chronological landmarks by which the could measure the passage of time. At some point he stopped being able to remember what happened even the day before. … As time began to blur, he became effectively amnesic. Soon, his sleep patterns disintegrated. Some days he’d stay awake for thirty-six straight hours, other days for eight – without being able to tell the difference. When his support team on the surface finally called down to him on September 14, the day his experiment was scheduled to wrap up, it was only August 20 in his journal. He thought only a month had gone by. His experience of time’s passage had compressed by a factor of two.
Monotony collapses time; novelty unfolds it. You can exercise daily and eat healthily and live a long life, while experiencing a short one. If you spend your life sitting in a cubicle and passing papers, one day is bound to blend unmemorably into the next – and disappear. That’s why it’s important to change routines regularly, and take vacations to exotic locales, and have as many new experiences as possible that can serve to anchor our memories. Creating new memories stretches out psychological time, and lengthens our perception of our lives.
Within the category of declarative memories, psychologists make a further distinction between semantic memories, or memories for facts and concepts, and episodic memories, or memories of the experiences of our own lives. Recalling that I had eggs for breakfast this morning would be an episodic memory. Knowing that breakfast is the first meal of the day is a semantic memory. Episodic memories are located in time and space: They have a where and a when attached tot them. Semantic memories are located outside of time and space, as free-floating pieces of knowledge. These two different types of remembering seem to make use of different neural pathways, and rely on different regions of the brain, though both are critically dependent on the hippocampus and other structures within the medial temporal lobes.
It’s thought that sleep plays a critical role in this process of consolidating our memories and drawing meaning out of them. Rats that have spent an hour running around a track apparently run through the same track in their sleep, and exhibit the same patterns of neural firings with their eyes closed as when they were learning the mazes in the first place. It has been suggested that the reason our own dreams so often feel like a surreal recombination of elements plucked from real life is that they are just the by-product of experiences slowly hardening into long-term memories.
Most of the evolution that shaped the primitive brains of our prehuman ancestors into the linguistic, symbolic, neurotic modern brains that serve us (sometimes poorly) today took place during the Pleistocene, an epoch which began about 1.8 million years ago and only ended ten thousand years ago. During that period – and in a few isolated places, still to this day – our species made its living as hunter-gatherers, and it was the demands of that lifestyle that sculpted the minds we have today.
What our early human and hominid ancestors did need to remember was where to find foo and resources, and the route home, and which plants were edible and which were poisonous. Those are the sorts of vital memory skills that they depended on every day, and it was – at least in part – in order to meet those demands that human memory evolved as it did.
The principle underlying all memory techniques is that our brains don’t remember all types of information equally well. As exceptional as we are at remembering visual imagery… we’re terrible at remembering other kinds of information, like lists of words or numbers. The point of memory techniques is to…take the kinds of memories our brains aren’t good at holding on to and transform them into the kinds of memories our brains were built for.
In Australia and the American Southwest Aborigines and Apache Indians independently invented forms of the loci method. But instead o fusing buildings, they relied on the local topography to plot their narratives, and sang them across the landscape. Each hillock, boulder, and stream held a part of the story. “Myth and map became coincident,” says John Foley, a linguistic anthropologist at the University of Missouri who studies memory and oral traditions. One of the tragic consequences of embedding narrative into the landscape is that when Native Americans had land taken from them by the U.S. government, they lost not only their home but their mythology as well.”