What is Memory?

I’ve been studying neurology (how the brain works) as an avocation for almost fifty years. The most remarkable thing I can say about this curious passion is how little we still know about how the brain works and how much we’ve discovered in the last two decades, especially with the advent of functional magnetic resonance imaging (fMRI) which tells us what the brain is doing while we’re thinking (such as we do when we access our memories).

We are our memories, not just our imagined past but our desired futures. Memory is more than a repository of thoughts about who we believe we are; it’s a dynamic creative force that shapes the stories of our lives. What’s unique about humans is our ability to see the past while creating visions for our futures. Memories are both abstract and concrete – a composite of thousands of facts, trivia, sensations and experiences, both relevant and inconsequential. They consist of thousands of neuronal connections (called memory traces) containing voices, scenes, smells and emotions – both happy and sad.

The temporary collector and coordinator of what we remember is the hippocampus (more accurately the hippocampi, because we have two of them). Discovered in 1564 by an Italian doctor, Julius Caesar Arantius, the name in Latin means “horse sea monster” because of its odd shape. This part of the brain holds our memories while they mature and decides which ones to keep and which to forget, a process that can take up to three years. Much like spring cleaning, the hippocampi determine what we keep and what we toss.

Our memories are malleable and inaccurate – a mix of fact and fiction – and hence unreliable. Their fate is determined by how much they mean to us. The ones that prevail are those that contribute meaningfully to the autobiography we want to write. Every time we recall one, the brain subconsciously mixes up the information fragments we already have, fills in the gaps with probable facts, then reconstructs or overwrites the original memory, offering up a slightly newer version that coincides with our self-image. Emotionally charged memories are “softened” over time by removing negative associations. Which of our memories are true and which are not is something we may never know.

The more time passes, the more we fantasize. Our memories are the prerequisites of our mental time travel to the future, because what we know of the past helps us forecast our future. We make things up, include things we haven’t really experienced and transform our memories into the tales we want to believe are us. In other words, we often remember things that never happened. Memory is not a vault of recollections; it’s actually a creative sponge that renews itself every time we seek a reassuring remembrance of things past.

Humans are visionaries. The basis for our beliefs and hopes for tomorrow lie in our recollections – they fuel our imagination of what could be. Imagination is the energy that brings old memories into the present. Remembering is imagining what might have happened as the fragments of the past are woven together and transformed into a coherent story. We spend more than half our waking hours letting our minds wander between imagined experiences of the past and future scenarios of what might one day happen to us. Our memories enable us to look both backwards and forwards.

Forgetfulness is underrated. We forget for a good reason: If we could not, the storage space in our brains would fill up. Every day, the population of the world produces more than 2.5 billion gigabytes of data but the brain’s estimated capacity for information is limited to about one million GB. While forgetting is something many fear, because they see it as decay or impermanence, if we cannot we wouldn’t be able to free up the needed space in our limited-capacity brains to remain open for new thoughts to take up residence. Forgetting enables us to not be enslaved by our memories. Worrying about memory loss is largely a symptom of our sometimes ridiculous standards of wanting perfection in all things. Nothing is perfect.

Our working (short-term) memory has a storage capacity of about three to five bits of data and it decides what’s worth saving and what’s not. That choice occurs within twenty to thirty seconds, depending upon one’s age. The brain prefers visualization of data as the optimal learning technique – 82% of the inputs are images and around 75% of what we do remember is visual.

Hermann Ebbinghaus, a German psychologist, pioneered the study of memory and is best known for his discovery of the forgetting curve, regarded by many as “The most brilliant single investigation in the history of experimental psychology.” Based on an exhaustive analysis, he stipulated that about 40% of the information entering our brains is gone within one hour and 70% disappears after one day. So how can you strengthen your memory? Whether you want to be a Jeopardy champion or just recall where you parked your car, there are things you can do to transform your mind from a sieve into a steel trap.

For starters, both the quantity and the quality of sleep have a profound impact on our memories in two ways: a sleep-deprived person cannot focus attention and sleep also has a critical role in memory consolidation, which is essential for learning new information. A lack of sleep leads to a 40% deficit in our ability to remember. Many researchers believe the characteristics of brain waves during different sleep stages strengthen the formation of particular types of memory (there are six types of memory that are assembled by different neuronal networks).

Poor memory and learning disorders have been linked in recent research to the over-consumption of sugar. Although our brains need glucose to power our thinking, the enemy is added (or “free”) sugar which reduces the production of a brain chemical known as brain-derived neurotrophic factor (BDNF). Without this, our brains can’t form new memories or remember much of anything.

Studies also show that eight seconds is the minimum amount of time it takes for a piece of information to go from our short-term memory to our long-term memory. So learn to deliberately concentrate by writing down what you want to remember in longhand. It doesn’t matter if you never read what you write: the simple act of writing something allows you to recall it in a way that touching a keyboard does not. As noted, try to visualize. This includes doodling. While it may seem that doodlers pay less attention, drawing our thoughts keeps the brain active and research suggests it improves recall by a third.

Our memory adapts to what we need it for, even as we grow older. Our stem cells give birth to new memory neurons. So an active life with an eclectic interest in a broad array of different things and an active imagination are the primary sources of a stronger memory. A mountain of scientific studies tell us that extreme learning leads to extreme remembering.