If you ask your friends about their favorite memories, they may mention their first kiss, a wedding day, or perhaps even giving birth to their child. It’s usually an important moment in time.
But how does that process of remembering work?
A common misconception is that when we try to remember a past event, our brain just pops in a DVD so we can re-watch the “movie” in our minds.
However, that’s not the case. Instead, each part of a memory — like the smell, sound or taste — is stored in a different section of our brain. And then all these sections are tied together, connected at the hippocampus.
When you recall a memory, your hippocampus pulls on the respective strings and your brain attempts to reassemble that moment.
Since you are literally rebuilding your memories from the blueprints in the hippocampus, your experience with the triggered memory can differ from day to day.
Sometimes you might focus on a sound, whereas other times you’ll think about the smell. It really just depends on what triggered that memory in the first place.
What exactly is a memory?
A memory is what we call the brain’s ability to encode, store, and retrieve information. And not all memories are alike.
When you try to hold a limited amount of information for a brief period of time, such as logging a new phone number, you’re using your working memory.
Long-term memories are typically organized into two categories: declarative and nondeclarative memories.
Declarative memories are our conscious memories. These are things that you might need to actively think about. For example, if you were asked, “Who was the first woman to win a Nobel Prize?”, you could use a declarative memory to identify the answer, Marie Curie.
Nondeclarative memories are unconscious. They’re what allow you to unbutton your shirt without thinking about the specific movements of your fingers.
In general, “knowing how” is nondeclarative and “knowing that” is declarative.
But scientists can also distinguish a few different categories of long-term memories, which together can explain how humans operate. Those include:
- Procedural memories (AKA muscle memory): what we use when we throw a ball, type on the keyboard, and learn a new instrument.
- Priming: when a previous memory affects our interaction with a current item
- Classical conditioning: where we pair two stimuli, just like Pavlov did when he trained his dogs to salivate at the sound of a bell.
- Semantic memories: facts that you know, but you likely don’t remember when or how you learned them.
- Episodic memories: the time travel type, where you connect a date with an emotional experience (like dancing in the rain on your wedding day)
And we aren’t the only species with these abilities. Some research points to birds also recalling episodic memories.
How can we improve our memory?
Dr. Elizabeth Kensinger is a professor of psychology and neuroscience at Boston College, and she has a lot of tips for how we can help our hippocampus encode, consolidate and store, and retrieve a specific memory.
“By and large, if you want to form a memory, you want to be getting it into your working memory, which means paying attention to it, thinking about it,” she says.
That’s why, when you’re doing something like studying for a test, it’s important to limit distractions and not multitask.
Kensinger suggests focusing on the two P’s: “pay attention” and “practice.” You’ll need to put in effort in order to turn a short-term memory into a long-term one.
And don’t forget to sleep! Your brain consolidates and stores memories while you are unconscious at night.
But how do we know all this? This research dates back to a lobotomy in the 1950s, which ripped the field wide open.
To learn more about cracking the code of memory and its connection to the hippocampus, check out the latest episode of Seeking A Scientist.
Additional sources from Seeking A Scientist:
- Brain Anatomy and How the Brain Works
- Memory: An Extended Definition
- Kausik Si
- Stowers Institute
- Muscle Memory
- From Knowing to Remembering: The Semantic-Episodic Distinction
- The Neurobiology of Semantic Memory
- Episodic Memory: Definition & Examples
- The Three “Ws” of Episodic Memory: What, When, and Where
- Episodic-like Memory During Cache Recovery by Scrub Jays
- Social Learning Spreads Knowledge about Dangerous Humans Among American Crows
- How Does Short-term Memory Work in Relation to Long-term Memory?
- Formation of Long-term Memory without Short-term Memory Revealed by CaMKII Inhibition
- Working Memory
- Associations and Memory
- The Seahorse in Your Brain: Where Body Parts Got Their Names
- Procedural Memory
- Elizabeth Kensinger - Remembering H.M.
- Semantic Knowledge in Patient H.M. and Other Patients with Bilateral Medial and Lateral Temporal Lobe Lesions
- Inside the Science of Memory
- Memories Involve Replay of Neural Firing Patterns
- Memory Consolidation
- The Nature of Short-term Consolidation in Visual Working Memory
- The Neurobiological Foundation of Memory Retrieval
- Brain Areas Associated with Memory
- Why Music Causes Memories to Flood Back
- False Memory in Psychology: Examples & More
- Learning and Memory Under Stress: Implications for the Classroom
- Stress and Long-term Memory Retrieval: A Systematic Review
- Are Eyewitness Accounts Biased?
- Why We Remember - and Forget. And What We Can Do About It
- Emotional Memory
- Fire Bubbles - The Methane Mamba
- Cognitive Neuroscience of Emotional Memory
- Beyond Fear Emotional Memory Mechanisms in the Human Brain
- The Tip-of-the-Tongue Feeling May Be an Illusion
- The New Science of Forgetting
- 10 Early Signs and Symptoms of Alzheimer’s and Dementia
- Changes of Behaviour in the Later Stages of Dementia
- Alzheimers’s: Medicines Help Manage Symptoms and Slow Decline
- Dementia
- Protect Your Brain From Stress
- Icona Pop
- I Love It by Icona Pop
- Lionel Messi
- Lost
Seeking A Scientist is a production of KCUR Studios. It's made possible with support from the Stowers Institute for Medical Research, where scientists work to accelerate our understanding of human health and disease.
It's hosted by Dr. Kate Biberdorf, AKA Kate the Chemist. Our senior producer is Suzanne Hogan. Our editor is Mackenzie Martin. Our digital editor is Gabe Rosenberg. This episode was mixed by Olivia Hewitt and Suzanne Hogan.
Additional support from David McKeel, Byron Love, Allison Harris and Genevieve DesMarteau.
Our original theme music is by The Coma Calling. Additional music from Blue Dot Sessions.
