Your brain is amazing. Every day, it performs miracles— it sees, hears, tastes, smells, and senses touch. It also feels pain, pleasure, temperature, stress, and a wide range of emotions. It plans things and solves problems. It knows where you are in space so you don’t bump into walls or fall down when you step off a curb to cross the street. It comprehends and produces language. It mediates your desire for chocolate and sex, your ability to empathize with the joy and suffering of others, and an awareness of your own existence. And it can remember. Of all the complex and wondrous miracles that your brain executes, memory is king. 

You need memory to learn anything. Without it, information and experiences can’t be retained. New people would remain strangers. You wouldn’t be able to remember the previous sentence by the end of this one. You depend on memory to call your mother later today and to take your heart medication before you go to bed tonight. You need memory to get dressed, brush your teeth, read these words, play tennis, and drive your car. You use your memory from the moment you wake up until the moment you go to sleep, and even then, your memory processes are busy at work. 

The significant facts and moments of your life strung together create your life’s narrative and identity. Memory allows you to have a sense of who you are and who you’ve been. If you’ve witnessed someone stripped bare of his or her personal history by Alzheimer’s disease, you know firsthand how essential memory is to the experience of being human. 

But for all its miraculous, necessary, and pervasive presence in our lives, memory is far from perfect. Our brains aren’t designed to remember people’s names, to do something later, or to catalog everything we encounter. These imperfections are simply the factory settings. Even in the smartest of heads, memory is fallible. A man famous for memorizing more than a hundred thousand digits of pi can also forget his wife’s birthday or why he walked into his living room. 

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. You remember even less from five years ago. 

And much of what we do remember is incomplete and inaccurate. Our memories for what happened are particularly vulnerable to omissions and unintentional editing. Do you remember where you were, who you were with, and what you were doing when President Kennedy was killed, when the space shuttle Challenger exploded, or when the Twin Towers collapsed on September 11, 2001? These recollections for shocking and emotional events feel vividly remembered even years later. But if you’ve ever reminisced about that day or read or watched a news report about it, then I’d bet every penny I’ve got that your confidently held, highly detailed memory is loaded with stuff you never actually experienced. 

Accuracy aside, what does your brain remember?

Your first kiss 
The answer to 6 × 6 
How to tie your shoes 
The day your son was born 
The day your grandmother died 
The colors of the rainbow 
Your address 
How to ride a bike

What does your brain most likely forget?

Your tenth kiss 
What you had for dinner last Wednesday 
Where you put your phone 
The name of your fifth- grade teacher
The name of the woman you met five minutes ago 
Algebra
 To take out the trash 
The Wi- Fi password 

Why do we remember our first kiss but not our tenth? What determines what we remember and what we forget? Memory is quite economical. In a nutshell, our brains have evolved to remember what is meaningful. They forget what isn’t. The truth is, much of our lives are habitual, routine, and inconsequential. We shower, brush our teeth, drink coffee, commute to work, do our jobs, eat lunch, commute home, eat dinner, watch TV, spend too much time on social media, and go to bed. Day after day. We can’t remember anything about the load of laundry we did last week. And that’s OK. Most of the time, forgetting isn’t actually a problem to solve. 

We would probably all agree that forgetting our tenth kiss, last week’s laundry, what we ate for lunch on Wednesday, and whatever is on the head of a penny isn’t such a big deal. These moments and details aren’t particularly significant. However, our brains also forget plenty of things we do care about. I would very much like to remember to return my daughter’s overdue library book, why I just walked into the kitchen, and where I put my glasses. These things matter to me. In these instances, we often forget not because it’s efficient for our brains to do so but because we haven’t supplied our brains with the kinds of input needed to support memory creation and retrieval. These garden- variety memory failures are normal outcomes of our brains’ design. But we seldom think of them this way because most of us aren’t familiar with our memory’s owner’s manual. We would remember more and forget less if we understood how the process works. 

Most of what we forget is not a failure of character, a symptom of disease, or even a reasonable cause for fear— places most of us tend to go when memory fails us. We feel worried, embarrassed, or plain scared every time we forget something we believe we should remember or would have remembered back when we were younger. We hold on to the assumption that memory will weaken with age, betray us, and eventually leave us. 

As both a neuroscientist and the author of Still Alice, I’ve been talking to audiences around the world about Alzheimer’s disease and memory for over a decade. Without exception, after every speech, people wait for me in the lobby or corner me in the restroom to express their personal concerns about memory and forgetting. Many have a parent, a grandparent, or a spouse who had or has dementia. They have witnessed the devastation and the heartache caused by profound memory loss. When these folks can’t remember their Netflix password or the name of that movie starring Tina Fey, they worry that these failures might be early signs that they, too, are succumbing to inevitable disease. 
Our fears around forgetting aren’t only about a dread of aging or Alzheimer’s. They’re also about losing any of our memory’s capability. Because memory is so central to our functioning and identity, if you start becoming forgetful, if you begin forgetting words and start losing keys and glasses and your phone, the fear is this: I might lose myself. And that’s justifiably terrifying. 

Most of us paint forgetting as our mortal adversary, but it isn’t always an obstacle to overcome. Effective remembering often requires forgetting. And just because memory sometimes fails doesn’t mean it’s in any way broken. While admittedly frustrating, forgetting is a normal part of being human. By understanding how memory functions, we can take these inconvenient gaffes in stride. We can also learn to prevent many episodes of forgetting by eliminating or artfully navigating around common errors and bad assumptions. 

When I explain to folks why they forget things like names, where they parked their car, and whether they already took their vitamin today, when I describe how memory is created and retrieved and why we forget— not because of disease pathology but because of how our brains have evolved— they audibly exhale. They look relieved and grateful, changed by this information. They leave me unafraid, holding a new relationship with their memory. They are empowered. 

Once we understand memory and become familiar with how it functions, its incredible strengths and maddening weaknesses, its natural vulnerabilities and potential superpowers, we can both vastly improve our ability to remember and feel less rattled when we inevitably forget. We can set educated expectations for our memory and create a better relationship with it. We don’t have to fear it anymore. And that can be life changing.