Long-Term Memory

You remember it like it was yesterday, the day you won the 5th-grade spelling bee. On your bike home from school, you pedaled as fast as you could, fueled by the excitement of telling your parents you had qualified for regionals. The word you nailed? “Paraphernalia,” luckily, you had been rehearsing it over and over the night before, until it finally stuck. You burst through the door, ready to share your big news, but your parents don't even hear you at first. Their eyes are glued to the TV as it covers a devastating earthquake that struck just over an hour ago. To this day, you still remember the word “paraphernalia”, the freeing feeling of flying home on your bike, and the exact expression on your mother's face as she watched the news. Why? Because so many forms of long-term memory were activated in that moment. 

So, how do different types of long-term memory manifest? Ever wondered how you can type so fast or shut your brain off when you drive home? It's your procedural memory at work.² It improves efficiency when performing repeated tasks, by storing information subconsciously without you even realizing it. Just like biking home from school, focused on sharing the good news with your parents, you aren’t thinking about the directions. 

On the other hand, sometimes active recall is necessary to reach a memory that's been stored in your long-term archive, like the capital of Spain being Madrid, or how to spell "paraphernalia." Through consistent learning, facts and concepts can become long-term knowledge, which is what we refer to as semantic memory.³ 

Our enhanced attention and hormones during emotionally salient events (like winning the spelling bee) affect the consolidation of memories. This is exacerbated during extremely emotionally charged events, when we form something called flashbulb memories—a type of episodic memory that is characterized by exceptionally vivid and detailed mental snapshots of the moment when we learned shocking news,⁴ like the occurrence of a fatal Earthquake. 

How do memories become long-term? 

All long-term memories begin in the hippocampus, located in the brain's temporal lobe. There are three steps to long-term memory:

1. Encoding: The process of transforming information into a form that can be memorized, like making up songs to help you remember vocabulary in a different language.
2. Storage: Maintaining the information over time. Even if you haven't skied or skateboarded in years, you still remember how. 
3. Retrieval: Accessing and bringing stored information into your conscious awareness, like remembering the times tables when calculating how much money you owe a friend.⁵ 

Consolidation occurs between encoding and storage, and it's the process that allows memories to transition from the short-term to the long-term. It takes place at three main levels:

• Synaptic consolidation (the cellular level): Within minutes or hours of learning new information, like someone's name, your brain chemically “locks in” a new memory trace by strengthening synapses between neurons. 
• Systems consolidation (the network level): Over days, weeks, months, or even years, your brain will gradually reorganize where this information is stored, usually transferring it from the hippocampus to the cortex. For example, eventually, you may just “know” your friend's address automatically without even having to think about it. 
• Sleep-dependent consolidation: During sleep, the brain actively reviews and strengthens memories, helping them integrate new information deeply into long-term storage.⁶

We have a foundational understanding of long-term memory, but much about it remains to be discovered. Ongoing research explores how to improve LTM and how different factors like sleep, nutrition, and mental health play a role, especially in efforts to slow cognitive decline caused by conditions such as Alzheimer's. Other contemporary research is focused on how, with advancements in AI and digital technology, our outsourcing of memory to digital devices is having an impact on our long-term encoding and storage, raising important questions about the future of our cognitive health in a tech-driven world.