Do You Think You Know Yourself? Think Again.

"It is singular how soon we lose the impression of what ceases to be constantly before us. A year impairs, a luster obliterates. There is little distinct left without an effort of memory, then indeed the lights are rekindled for a moment — but who can be sure that the Imagination is not the torch-bearer?"
 ~Lord Byron

Memories -- so common and yet so mysterious. What is a memory? Why do some things -- even the most trivial moments -- make indelible memories while others fade? How accurate to the actuating occurrence are memories? As memories occupy a significant part of human existence, they remain but ethereal ghosts of recollection.

The history of the word memory includes derivation from the Old Norse word Mimir. In Norse mythology, Mimir is a giant who guards the well of wisdom. According to one legend Mimir is beheaded by the enemies of the gods of Asgard during the Æsir-Vanir War, a conflict between two groups of deities. His head is then preserved by Odin, who consults it for information and advice.

Without a legendary automation like a brazen head or a separate wise cranium like Mimir, we humans rely upon memory stored in their own brains to retain information and reconstruct past experiences, usually for present purposes. Of course, memory is one of the most important ways by which our histories animate our current actions and experiences.

Nearly 300 years ago, Scottish philosopher David Hume, in his seminal work “A Treatise of Human Nature,” offered a radical notion of human identity: that the “self,” as we conceive of it, is not a single spiritual or psychological entity, like a “soul,” but rather a collection of discrete sensations and impressions -- a “bundle,” as he called it. Connections between these individual perceptions give rise to the idea of a continuous “self.” And memory gives that self lasting force.

What, then, is any one of us a person -- a "self" -- without our memories?

John Locke (1632-1704), English philosopher and physician regarded as one of the most influential of Enlightenment thinkers, posited that what makes us the same person yesterday is "that we can remember what we did or experienced yesterday." So, for Locke, memory is what actually determines who we are. He considered personal identity (or the "self") to be founded on consciousness (in other words "memory") and not on the substance of the soul or the body.

However, all of us have found our "selves" in conscious memory fails. Although some of these unexpected occurrences leave us blank and frantically searching for a spark to initiate recall, we also understand that memories we easily recollect experience a life of alteration with age. Research is discovering what we think we know may be just that -- only what we "think," not necessarily accurate and constant to the original experience.

What Happens When We Think?

In five decades of research, Eric Kandel, a neuroscientist at Columbia University and Nobel Prize winner in Physiology or Medicine, has shown how our short-term memories -- those lasting a few minutes -- involve relatively quick and simple chemical changes to the synapse that make it work more efficiently.

Kandel found that in order for us to build a memory that lasts hours, days or years, neurons must manufacture new proteins and expand the docks to make the neurotransmitter traffic run more efficiently. Long-term memories must literally be built into our brain’s synapses. Kandel and other neuroscientists have generally assumed that once one of our memories is constructed, it is stable and can’t easily be undone. Or, as they put it, that memory is “consolidated.”

Here is a simple analogy:

"According to this view, the brain’s memory system works something like a pen and notebook. For a brief time before the ink dries, it’s possible to smudge what’s written. But after the memory is consolidated, it changes very little. Sure, memories may fade over the years like an old letter (or even go up in flames if Alzheimer’s disease strikes), but under ordinary circumstances the content of the memory stays the same, no matter how many times it’s taken out and read.

(Greg Miller. "How Our Brains Make Memories." Smithsonian Online. April 29, 2010)

"Memories, particularly important ones, are not like photographs

that freeze a moment in time: they are more like keepsakes

that are reframed with each new look."

--Don Narey

Neuroscientist Karim Nader challenges Kandel's idea. He and his colleagues believe a memory is re-formed in the process of calling it up. In other words, Nader believes that a memory changes every time we think about it. He posits that memories could be unfixed and "reconsolidated" -- a notion that flouted 100 years of conventional wisdom in his field. Nader even suggests that reconsolidation may be the brain’s mechanism for recasting old memories in the light of everything that has happened since. In other words, it just might be what keeps us from living in the past.

Nader says as a memory is rewired, we can add false information to it, make it stronger, make it weaker, and possibly even make it disappear. So when we think about something from the past, the memory is called up like a computer file, reviewed and revised in subtle ways, and then sent back to the brain's archives, now modified slightly, updated, and changed.

Nader discovered that a fear memory induced in a rat and reactivated after 1-12 days of storage in the outer part of the brain could be eradicated with a shot of anisomycin, a protein-synthesis inhibitor.

"Imagine the possible benefit for people traumatized by haunting memories of terror or tragedy. The day may come when the cure is recalling the trauma, and then erasing it with a shot," wondered Dallas Morning News reporter Tom Siegfried.

Legendary film director, Luis Bunuel, writing his autobiography in his eighties, offered up this disclaimer:

“Our imagination, and our dreams, are forever invading our memories; and since we are all apt to believe in the reality of our fantasies, we end up transforming our lies into truths…I am the sum of my errors and doubts as much as my certainties. Such is my memory.”

What could we know of ourselves without memory? Still, even though we rely upon our memory to reason, each recall of a past experience is likely to alter what we understand about it. Perhaps most memories are filled with emotion, and this emotion changes with time. In any event, research makes us question what really comprises the knowledge and reasoning stored in our minds.

While it is somewhat frightening to face alterations since we may distrust the accuracy of our memories, we possess a brain that must be able to rearrange itself, establishing new connections while weeding out old ones. And, since there is a constant decay of memory traces over time, reactivation of the synapses strengthens new thought transmission -- it is much-needed exercise for keeping fit the gray matter in the aging, increasingly forgetful noggin.