13-04-2025
Why we forget things – and how to remember better
Have you ever walked into a room and immediately forgotten why you were there? Congratulations! You're human. Memory is the incredible mental filing system that lets us recall birthdays, algebra formulas, and exactly where we left the last piece of cake in the fridge. But it's also frustratingly unreliable. We forget passwords, where we park our cars, and sometimes even people's names five seconds after they introduce themselves.
Memory works in three stages: encoding, storage and retrieval. Encoding happens when your brain processes sensory input and decides whether it's worth saving. Storage determines if it stays short-term (like where you left your keys) or long-term (like your childhood best friend's home phone number from 20 years ago). Retrieval is when you try to recall information.
Forgetting isn't just an annoyance; it's how the brain stays efficient. Scientists have different theories on why it happens. Decay theory says unused memories fade, like a dusty old treadmill. Interference theory suggests new memories can overwrite old ones, or vice versa, which is why you remember your high school phone number but not your new one.
Retrieval-induced forgetting happens when recalling one memory blocks another, like when you can't remember an actor's name but recall all their movies. Cue-dependent forgetting ties memory to context, which is why you recognise a face but forget where you met them. While frustrating, forgetting is just your brain optimising what matters, sometimes a little too aggressively.
German psychologist Hermann Ebbinghaus spent years testing memory to map out the Forgetting Curve, which shows that we forget most information within hours of learning it unless we reinforce it. Modern research builds on this with Bjork's Desirable Difficulties, which proves that making learning harder actually helps memory retention. Basically, if you want to remember something, make it slightly annoying to learn.
Think of your hippocampus as the brain's librarian, filing and retrieving memories. Studies on London taxi drivers show that their hippocampus literally grows from all the navigation skills they develop.
Meanwhile, age-related forgetting happens because neural connections weaken over time, but research suggests we can stimulate memory by keeping our brains active. Your brain does its best memory magic while you sleep, which is why pulling an all-nighter is like throwing your notes into a blender.
A Hong Kong study found that targeted memory reactivation (TMR) during sleep can strengthen or weaken memories. Meanwhile, exercise increases blood flow to the brain, improving recall. And emotions? Well, that's why you remember embarrassing moments from middle school but not what you had for lunch yesterday. Your brain has a flair for the dramatic.
Would you really want to remember every single detail of every single day? Forgetting helps you prioritise what matters. AI research on catastrophic forgetting shows that when systems remember everything, they become overwhelmed. Your brain smartly prunes unimportant details so you don't have to. It's a survival feature, not a flaw, so next time you forget someone's name, just say you are optimising brain efficiency.
Could science one day help us selectively erase memories, like a real-life 'Eternal Sunshine of the Spotless Mind?' Researchers think so. Techniques like memory reconsolidation disruption and optogenetics (using light to edit memory) suggest that in the future, we might actually be able to erase painful or unnecessary memories. Ethical concerns aside, it's a fascinating field, though it might also mean you would have to set reminders for why you erased something in the first place.
If you want to remember more and forget less, work with your brain, not against it. Retrieval practice makes memories stronger, while mnemonic devices help by turning dull facts into memorable images.
Exercise and sleep also play a role, boosting blood flow to the brain and consolidating memories. Contextual learning shows that studying in different places improves recall by reducing reliance on a single set of cues. Lastly, managing stress is key; too much cortisol can block memory retrieval, causing those dreaded blank-out moments. So, test yourself, stay active, switch up your environment and get enough rest; your brain will thank you!
