Imagine your brain as an attic, a space where you store memories. This was the idea of Sherlock Holmes, the famous detective, who believed that filling your brain with trivial facts could leave less room for important information. But is this true? Is our memory really limited, or is it boundless? And what would life be like if we never forgot anything?
In the animated film Inside Out, memories are depicted as glowing spheres, neatly organized in the brain. However, the reality is far more complex. Memories aren’t stored in a single location in the brain. Instead, they are distributed across various regions, with different brain cells working together to form a single memory. For instance, the memory of enjoying your grandma’s apple pie involves different cells for the pie’s appearance, the cinnamon’s aroma, and the pie’s taste.
Think of a memory as an action rather than a physical object. It’s like a wave at a baseball game—no single fan is the wave; it only exists when everyone participates in a coordinated manner. Similarly, a memory forms when neurons fire in a specific pattern. This means that the same group of neurons can store multiple memories, enhancing the brain’s storage capacity.
Deep within the brain lies the hippocampus, a seahorse-shaped structure crucial for forming new memories. Our understanding of its role comes from a patient known as H.M., who lost most of his hippocampus during surgery for epilepsy. Post-surgery, H.M. couldn’t form new memories but retained those from before the operation. This revealed that while the hippocampus is essential for creating memories, it isn’t where they are stored.
When a mouse navigates a maze, its brain cells activate in specific patterns. Later, these patterns replay, strengthening connections between cells—a process called consolidation. This is how experiences become long-term memories. A familiar scent, like cinnamon, can trigger these patterns, recalling memories, just as it might remind you of your grandma’s kitchen.
Our brains are adept at forgetting, which is as crucial as remembering. Forgetting can occur passively over time as connections between brain cells weaken, or due to interference when neurons are used in other memories. During sleep, we engage in targeted forgetting, clearing out unnecessary information. This helps us update our mental models and discard outdated beliefs.
Motivated forgetting is when we intentionally suppress unpleasant memories to maintain emotional balance and focus on the present. While we don’t fully understand how this works, it involves blocking the retrieval of distressing memories.
Forgetting is vital for moving past traumatic events and preventing information overload. Without it, our brains would be overwhelmed with trivial details, as Sherlock Holmes suggested. Forgetting allows us to replace old information with new, more accurate knowledge.
Some individuals, like Jill Price, have a rare condition called hyperthymesia, where they remember nearly everything. While this might seem advantageous, it can be burdensome, as they can’t escape painful memories and regrets.
While perfect memory might seem desirable, it’s not the ultimate goal of learning. True understanding involves connecting concepts, exploring different interpretations, and adapting to new information. These skills are crucial for effective learning.
If you’re interested in enhancing your logical thinking and problem-solving skills, consider exploring courses on platforms like Brilliant. They offer engaging challenges that can help you develop a Sherlock Holmes-level of deduction.
Visualize your brain as an attic and create a mind map of your own memories. Identify different types of memories (e.g., sensory, emotional) and map them to various brain regions. This will help you understand how memories are distributed across the brain.
Engage in a group activity where you simulate the firing of neurons to form a memory. Assign roles to each participant as different neurons and create a pattern to represent a specific memory. This will illustrate how memories are formed through coordinated neural activity.
Analyze the case of patient H.M. and discuss the role of the hippocampus in memory formation. Reflect on how H.M.’s experience has shaped our understanding of memory and its storage. Present your findings in a group discussion.
Conduct a simple experiment to observe memory consolidation. Learn a new skill or piece of information, then take a break or sleep. Test your recall afterward to see how well the information has been consolidated into long-term memory.
Participate in a debate on the importance of forgetting. Discuss whether forgetting is beneficial or detrimental to learning and emotional well-being. Use examples from the article to support your arguments and consider the implications of hyperthymesia.
Thank you to Brilliant.org for supporting PBS Digital Studios. Sherlock Holmes, the legendary detective, had a theory that the brain is like an attic where a person can only store a limited amount of memories. Dr. Watson once told him that the Earth travels around the sun, to which Holmes replied, “Now that I do know it, I shall do my best to forget it.” Holmes figured that cluttering your attic with random facts and trivia leaves less room for the things that matter, like identifying the tiny differences between lethal poisons.
Was Holmes right? Is our memory limited, like the storage capacity of a computer? Or is our memory unlimited? And if we had perfect memory, what would life be like if we never forgot anything?
The animated film *Inside Out* depicted memories as glowing spheres stacked in the brain, like books in a library. But the reality is more complicated. There is no single place in the brain that serves as our memory bank. Instead, individual memories are scattered throughout the brain. Many brain cells in different regions work together to create one memory. For example, a memory of eating grandma’s apple pie might involve some brain cells to help you remember what the pie looked like, others to remember the smell of the cinnamon, and even cells to remember the delicious taste.
In reality, a memory isn’t a physical thing that we can find in any given brain cell. It’s an action, not an object. Think of baseball fans doing “the wave”: no single fan IS the wave; the magic only happens when all the fans are together, doing their thing in a specific order. Similarly, a memory only occurs when many connected neurons fire in a specific pattern. Because the same cells can fire in many unique patterns, one group of neurons can encode multiple memories, increasing the memory storage capacity of the brain.
Deep in the middle of the brain, we find a group of cells shaped like a seahorse, which is why 18th-century scientists named this area the ‘hippocampus.’ Without your hippocampus, you might never remember. We owe a lot of our understanding of memories to one famous patient known only by his initials, H.M. In 1953, H.M. underwent surgery for epilepsy that destroyed most of his hippocampus. For the rest of his life, he exhibited a severe type of amnesia where he was unable to form new memories of facts or events, but he could still remember things he had learned before the surgery. This showed us that the hippocampus is key to making memories, but it isn’t where memories are stored.
So how do experiences become memories? If we look inside the brain of a mouse in a maze, we could draw a kind of map showing which brain cells are active as the mouse experiences something. Later, we would see the mouse’s brain cells firing in the same patterns, replaying the experience in fast forward, over and over, to strengthen the connections between cells. This process is called consolidation, and it’s how animals—including humans—commit new memories to long-term storage. Days or weeks later, a smell might trigger this same pattern of nerve firing in the mouse’s brain, recalling the maze memories—just like smelling cinnamon might trigger memories of grandma for you.
However, the brain’s way of creating memories isn’t foolproof. Sometimes, our mental replay of something we only imagined can feel as vivid as a real experience. If you picture all the sights, smells, and sounds of a crime scene from someone’s description, you activate similar brain networks as if you had really been there. The more you replay the scene in your mind, the more it feels like a real memory. That’s why a detective who asks leading questions can inadvertently plant a false memory in a witness.
We’re able to remember a lot, but we forget even more. Some forgetting just happens, but our brains also forget on purpose. We have at least three different ways of forgetting. The first is what happens when a memory fades over time, known as “passive oblivescence.” This may occur because the connections between brain cells gradually weaken over time, or perhaps the memory is still there, but you might lose the triggers—sights, sounds, smells—you need to retrieve it.
Another idea suggests that memories could theoretically last forever, but when the same neurons are used in other memories, this “interference” disrupts the original memory. This slow fade type of forgetting happens to all of us eventually. A second type of forgetting—targeted forgetting—happens at night while we sleep. This is when we clear out random, useless bits of information we’ve learned during the day and erase outdated memories. For example, if yesterday you thought Earth was a flat disk supported by three elephants, and today you learned that the Earth is round, your brain needs to purge one of these contradictory ideas—hopefully, the one about the elephants.
In certain stages of sleep, we trim and prune connections between cells and erase unneeded memory circuits. The third type of forgetting is motivated forgetting, something we all wish we could do for one thing or another. This is when a person intentionally suppresses unpleasant memories. Forgetting on purpose helps regulate our emotions and allows us to focus on what needs to be done in the present, instead of getting lost in negative memories of the past. We may need motivated forgetting to maintain our self-image, confidence, optimism about the future, or to maintain relationships with people who have hurt us.
We don’t know exactly how motivated forgetting happens, but part of our brain seems to step in and block the troubling memory from being retrieved. So even though it’s still somewhere in our brain, eventually we can’t find it. Our brains have many ways to forget because forgetting is one of the most important things we do. Forgetting allows us to move past traumatic life events. In fact, PTSD may be a problem where someone simply remembers too much. Forgetting also allows us to clear out unnecessary information. Imagine every sight, sound, smell, and piece of information your brain processes every day! If our brains didn’t sweep out the garbage every night, we would soon overflow our neural networks with random trivia, just like Sherlock Holmes predicted.
We also wouldn’t be able to replace things that are no longer true with better information and update our mental models of the world. Deep in the scientific literature, we find stories of a handful of people who never forget anything. They are so rare that their unforgetfulness has a medical name: hyperthymesia. The most famous case is Jill Price, an American woman now in her fifties. Starting from age 14, Jill’s memory of her life is nearly perfect. For any date in the past, she remembers what she wore and had for lunch that day, key historical events she paid attention to, and detailed incidents from her life. She describes memories playing in her mind in vivid detail, like a video reel enhanced with smells and emotions, whether the events occurred yesterday or decades ago.
This might sound like a blessing, especially if you’re in school, but Jill has described being haunted by upsetting memories and regrets because, unlike the rest of us, she can clearly remember every choice she made and how it turned out. There’s probably something you truly want to forget, like that extremely embarrassing moment in high school that always seems to pop up at the worst times. Can we erase those unwanted memories somehow?
In an episode of *House, MD*, Dr. House treated a patient suffering from painful memories by performing something called electroconvulsive therapy: controlled electric shocks to the brain. People who undergo ECT do lose some memories—only not necessarily the ones they hope to lose. When it comes to erasing memories in humans, our best tool still works like a hammer, not a scalpel. It’s no accident that our ability to forget, like our ability to remember, is a complex and finely-tuned mechanism. If humans couldn’t remember and learn from important events, our species probably wouldn’t have survived. But it seems that being able to forget is just as critical, an elementary part of solving this great mystery we call life.
So you probably can’t teach yourself to have perfect memory and never forget anything—not without a massive brain injury or something. But is memorization really the best way to learn something? Memorizing can definitely help you get started with a new concept. However, truly understanding it requires much more—seeing how concepts are related to each other, looking for different interpretations, and dealing with new information. These are the skills that will help you learn anything, and if you’d like to sharpen your brain and develop these tools, then Brilliant could be the place to go for that.
Check out this Brilliant course on logic and deduction. It’s got fun and challenging riddles and mind-benders, broken up into bite-sized pieces, and they’ll guide you through the problems until you’re a Sherlock Holmes-level logical thinker. To support *It’s Okay To Be Smart* and learn more about Brilliant, go to Brilliant.org/BESMART and sign up for free. The first 200 people that go to that link will get 20% off the annual Premium subscription.
Memory – The cognitive process of encoding, storing, and retrieving information. – Researchers study memory to understand how past experiences influence behavior.
Hippocampus – A brain structure involved in the formation and retrieval of memories. – Damage to the hippocampus can severely impair the ability to form new memories.
Forgetting – The inability to retrieve information that was previously encoded and stored in memory. – Forgetting can occur due to interference or decay of memory traces over time.
Neurons – Specialized cells in the nervous system that transmit information through electrical and chemical signals. – Neurons communicate with each other to process and transmit information throughout the brain.
Consolidation – The process by which short-term memories are transformed into long-term memories. – Sleep is believed to play a crucial role in the consolidation of memories.
Experiences – Events or occurrences that leave an impression on an individual’s memory and influence their behavior. – Personal experiences can shape an individual’s perception and decision-making processes.
Emotional – Relating to feelings or emotions, which can significantly impact cognitive processes like memory and decision-making. – Emotional memories are often more vivid and enduring than neutral ones.
Learning – The process of acquiring new knowledge, behaviors, skills, values, or preferences. – Learning involves changes in the brain’s neural connections as a result of experience.
Connections – Links or associations between neurons that facilitate communication and information processing in the brain. – Strengthening neural connections is essential for effective learning and memory retention.
Information – Data that is processed and organized to have meaning, which can be stored in memory for future use. – The brain’s ability to process and store information is fundamental to cognitive functioning.
