Remember: The Science of Memory and the Art of Forgetting

by Lisa Genova

We hold on to the false assumption that memory will weaken with age, betray us, and eventually leave us.

Memory is the sum of what we remember and what we forget, and there is an art and science to both.

Alzheimer’s disease begins its rampage in the hippocampus. As a result, the first symptoms of this disease are typically forgetting what happened earlier today or what someone just said a few minutes ago and repeating the same story or question over and over. With an impaired hippocampus, people with Alzheimer’s have trouble creating new memories.

Long-term memories don’t reside in one particular neighborhood in your brain.

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.

If we want to remember something, above all else, we need to notice what is going on. Noticing requires two things: perception (seeing, hearing, smelling, feeling) and attention.

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.

The number one reason for forgetting what you just said, a person’s name, where you left your phone, and whether you already drove over a really big bridge is lack of attention. You can’t later remember what is right in front of you if you don’t pay attention to it.

Paying attention requires conscious effort. Your default brain activity is not attentive.

Whatever is held in your consciousness right now is called your working memory.

The holding capacity of working memory was first determined by George Miller in 1956, and his findings have stood the test of time. We can only remember seven plus or minus two things for fifteen to thirty seconds in working memory.

This isn’t how we read. The sentences you read are discarded from your working memory almost immediately after you read them.

We have three basic types of long-term memories: memory for information, memory for what happened, and memory for how to do things.

The stuff you know, so-called semantic memory, is memory for the knowledge you’ve learned, the facts you know about your life and the world—the Wikipedia of your brain. And you can recall this information without remembering the details of learning it. Semantic memory is knowledge disconnected from any personal when and where. It is data unattached to any specific life experience. Memories for what happened, for information that is attached to a where and when are called episodic. You remember episodic memories. “Remember when we went to Budapest.” Semantic memories, on the other hand, feel more like information that you just know. “Budapest is the capital of Hungary.” Episodic is personal and always about the past. Semantic memory is about information and is timeless. Just the facts, ma’am. For example, I know that the speed of light is approximately 186,000 miles per second. I pulled that information from semantic memory. If I could recall the specific circumstances of learning that nugget of information (I can’t), then that would be an episodic memory. Similarly, you know that George Washington was the first president of the United States, but you

Which is better for long-term retention—cramming the night before or studying the material spaced out over the seven days? If the total number of study hours is equal, distributed practice beats out cramming.

Episodic memory, your memory for what happened in your life, is the history of you remembered by you. It is memory tethered to a place and time, the where and when recollections of your life’s experiences. Episodic memory is time-traveling to your past. Remember when…

In general, the more emotional the event, the more vividly and elaborately detailed the memory.

Flashbulbs are episodic memories for experiences that were shocking and highly significant to you and evoked big emotions—fear, rage, grief, joy, love.

Strung together, your most meaningful episodic memories create your life story and are collectively called your autobiographical memory.

In terms of what happened, we remember almost nothing before the age of three and very little before the age of six. Our earliest episodic memories are the briefest short stories, sensory snapshots that are totally disconnected from the cohesive narrative starring you as the protagonist in your life. The average age for a first episodic memory that you can remember as an adult is three.

But most of life’s episodic memories are likely to be clustered between the ages of fifteen and thirty. Called the reminiscence bump, these episodes are what we remember most in life. Why is this? We don’t really know, but most scientists think it’s because so many meaningful firsts are packed into those years—kiss, love, car, college, sex, job, house, marriage, child. During these years, we begin to fill our life’s narrative with purpose and meaning. And again, our brains remember what is meaningful.

Forgetting is quite important; it helps us function every day in all kinds of ways. It’s advantageous for us to get rid of any unnecessary, irrelevant, interfering, or even painful memories that can potentially distract us or cause us to make mistakes or feel miserable. Sometimes we need to forget one thing in order to pay attention to—and remember—another, and so in this way, forgetting can facilitate better memory.