Remember: The Science of Memory and the Art of Forgetting

by Lisa Genova

In fact, most of us will forget the majority of what we experience today by tomorrow. Added

up, this means we actually don’t remember most of our lives. How many days, in full, specific detail, can you remember from last year? Most people recall an average of only eight to ten. That’s not even 3 percent of what you experienced from your recent past.

But retrieval isn’t like selecting an item on a DVD menu or a YouTube channel and pressing play. We don’t read our memories like a book or play them like a movie. Visual memory isn’t like looking through your smartphone photo library, a collection of photos that can be zoomed in on and out of. You’re not viewing a photograph. Remembering is an associative scavenger hunt, a reconstruction job that involves the activation of many disparate but connected parts of the brain. We remember memories; we don’t replay them.

Your memory isn’t a video camera, recording a constant stream of every sight and sound you’re exposed to. You can only capture and retain what you pay attention to. And since you can’t pay attention to everything, you’ll be able to remember some aspects of what is happening before you but not others.

Because we remember what we pay attention to, we might want to be mindful about what we focus on. Optimists pay attention to positive experiences, and so these events are consolidated into memory. If you’re depressed, you’re less likely to consolidate happy events or pleasant experiences into memory because happiness doesn’t jibe with your mood. You don’t even notice the sunnier moments when you’re only focusing on the dark clouds. You find what you look for. If you look for magic every day, if you pay attention to the moments of joy and awe, you can then capture these moments and consolidate them into memory.

When you test yourself and get the answer right, you’re retrieving information you’ve managed to learn, and through the act of recalling it, you’re reactivating the neural pathways of that memory, reinforcing them, making the memory stronger.

Your brain isn’t interested in knowing what’s boring or unimportant. If you want to know more stuff, make the information meaningful to you.

Almost half of Americans believe that the testimony—and therefore the memory—of a single eyewitness alone is enough to convict a defendant. As of September 2019, there have been 365 convicted, innocent people exonerated through DNA testing in the United States. Of those, approximately 75 percent had been found guilty on the basis of eyewitness testimony. Thus, all these eyewitness memories were wrong.

As you can see, with every recall, our memories for what happened can shrink, expand, and morph in all kinds of interesting and often inaccurate ways, deviating significantly from the original unspoken memory first created in our brains. Ironically, if you jot down what happened today, you’ll probably limit what you remember about today to the details you’ve chosen to record. Whatever you talk about will be reinforced, but that memory will deform as you continue to gab. But memories not repeated or shared at all are likely headed for the ash heap. When it comes to our memories for what happened, imperfect is the best our brains can do.

But there is also evidence that memories can be physiologically erased. More recent studies have shown that if the collection of synapses representing a memory isn’t activated over time, the connections will be physically pruned away. If dormant for too long, neurons will literally retract their anatomical, electrochemical connections with other neurons. The connections, and consequently the memory contained in those connections, will no longer exist.

But maybe you want to forget something. Let’s say your spouse cheated on you, and you got divorced. Want to forget the sordid details and the heartache you’re feeling? Stop repeating the story of what happened. Stop going over the details with your friends and in your thoughts. Don’t overlearn the experience. If you can find the discipline to leave those memories alone, they will eventually fade. And while you will always remember that your ex cheated on you, the emotional elements of that memory can gradually decay if left alone. It is through the erosion of memory that time heals all wounds.

So while we all want an amazing memory, we can’t put all the onus and credit on remembering. An optimally functioning memory system involves a finely orchestrated balancing act between data storage and data disposal: remembering and forgetting. When performing optimally, memory doesn’t remember everything. It retains what is meaningful and useful, and it discards what isn’t. It keeps the signal and purges the noise. Our ability to forget is likely to be just as vital as is our ability to remember.

People who have more years of formal education, who have greater literacy, and who engage regularly in socially and mentally stimulating activities have more cognitive reserve. They have an abundance and a redundancy of neural connections. So even if Alzheimer’s does compromise some synapses, they have many backup, alternate connections, which buffer them from noticing that anything is amiss. These folks have a reduced risk of being diagnosed with Alzheimer’s.