Memory is an astonishingly powerful thing. It allows you instantly call to mind events, emotions, songs, smells, first loves, first dates, and a thousand other things. In some senses, it is a mysterious thing. How can our brains call such powerful and vivid images to mind years after the fact?
While memory isn’t a physical object that can be studied like a plant or species of animal, we can analyze the cycle of remembering.
The concept of memory has evolved. Scientists initially believed that memory and the memory system existed in a single part of the brain. They illustrated the memory system by comparing it to a filing cabinet-- a single location where the brain went to access your memories.
However, scientists have found that the memory process is a cooperative effort from all parts of the brain and works more like a network. Your brain is not a single filing cabinet.
Learning new information requires that the brain access information from different parts of the brain’s neural web to construct what we call “memories.” This cohesive power works as a series of processes in the brain that work together to provide a single output.
For example, imagine taking a walk. As you walk, your brain is accessing various memories and stringing them together intelligently. You are remembering how to put one foot in front of the other. Maybe you’re remembering a route you took last week. You are subconsciously remembering how to keep yourself safe as your brain accesses all of these thoughts. You’re hearing and smelling and seeing things that are also triggering various memories.
Your brain, in an breathtaking feat of power and beauty, integrates all these memories as you walk.
While this process seems complex, it breaks down into three simple stages. If all parts work together, the memory system can create and recall your memories by encoding, storage, and retrieval.
Encoding is the most basic component of memory. This part of the process uses our base senses to process information. Any visual, auditory, or olfactory stimulation filters to the hippocampus for processing. Then, the sensory input combines into a singular experience. This is why certain songs or smells take you back to a specific time or place.
For example, if your grandmother always had chocolate chip cookies baking when you visited as a child, it’s possible that anytime you smell chocolate chip cookies, you recall your grandmother’s kitchen.
Your brain combined the smell of the cookies, the way her house looked, and the emotions you were experiencing into a single event-- a memory.
Once the brain has combined the incoming information, it is then responsible for analyzing the information. It must decide what information is important enough to store. Long-term memories of baking cookies with grandma are experiences that the frontal cortex analyzed and determined were “important.”
How Does Memory Analysis Work?
The study of the brain and its mysteries is constantly changing. However, scientists have concluded that the brain’s neural network involves 3 things: synapses, neurotransmitters, and dendrites.
All the action in your brain happens at the synapse level. A synapse is a location where your nerve cells connect. When an electric pulse stimulates a synapse, neurotransmitters release. Neurotransmitters are “chemical messengers” that then carry information to different parts of the brain.
Dendrites are the areas of the brain that receive the message sent by the neurotransmitters. This process is happening in every brain cell, creating thousands of links like this, giving a typical brain about 100 trillion synapses.
This process of connection across the brain’s network is constantly happening-- and just as quickly changing. This “plasticity “is what allows people to grow and learn. Every time a synapse sends information to a dendrite, their connection gets stronger. The new stimulation then adds connections in your brain cells.
As this process runs in the background, your frontal cortex is performing an analysis which allows the brain to not only organize thought and memories but also adapt its structure as new experiences are added.
The brain’s changing structure is what allows you to learn something new. Think about learning how to ride a bike. At first, the bike may wobble and fall. You can't ride ten feet. As your brain slowly processes the new experience it is also growing stronger.
Every time you access and use the part of the brain that stores your bike riding information, you are strengthening that neural pathway. As the pathway becomes stronger with use, you will eventually be biking down the sidewalk easily!
Thankfully, your brain is able to determine which things are worth encoding and which should be ignored. Think about your morning commute. If your brain were consciously choosing to process all sensory data you see or experience while driving, you would end up on the side of the road. The brain is able to instantaneously determine if input we are experiencing is significant enough to begin encoding.
Once information is encoded by the frontal cortex, the brain then evaluates how and where to store the input. This sorting process allows humans to function in daily life. There are three types of storage in the brain: sensory, short-term, and long-term
Sensory memory is the shortest storage unit for outside input. Scientists explain sensory memory as the initial impression left after experiencing external stimuli that functions as a “buffer” to filter input from our five senses.
The buffering performed by sensory memory is automatic on input and retains information for fractions of a second. Without it, the human brain would experience cognitive overload before you get out of bed in the morning!
Sensory memories last for less than a second. They are only retained when the brain consciously acknowledges the input as important and sends the information to short-term memory storage.
Short Term Memory
This type of memory can only retain a small amount of information - around 5-7 things - for a short period of time (twenty to thirty seconds). The most common example of this retention rate is evidenced by remembering a phone number.
The average U.S. phone number is 9 digits long. The short-term memory has have difficulty retaining the full number at once, so our brains break phone numbers down into three sections. It is much easier for the short term memory to remember three sets of shorter numbers than it is to retain a nine-digit number. Short term memory effectively allows your brain to not only remember input but also access the information simultaneously.
If a short term memory isn’t moved to long term memory, it too will disappear rather quickly, which is why we forget names so often. Some people take alpha gpc to boost choline levels in the brain which may influence memory in healthy individuals.
Long Term Memory
Your long-term memory houses the information the brain labels as “important”, and it is able to be retained over long periods of time. The long-term memory houses huge amounts of information that can be retrieved through a lifetime.
This memory process is the reason we are able to grow and learn through life. Repetition of information helps reinforce long-term memories. As we learn new information or have different experiences, the brain sends this input to a part of your memory that is related. This is why studying in school is important. After the brain encodes the first round of information, any additional learning reinforces the base memory. Because of its ability to grow over time, it is the long-term memory that truly shapes our life experience.
Once the brain moves through the process of encoding and storage, memories are ready to be accessed with the last step of the memory process -- retrieval. Remembering something requires that you mindfully decide which memory you will bring to your conscious attention. The process of encoding and analyzing helps the brain recall the memory you are trying to retrieve. The process of “forgetting” occurs when one part of the memory system isn’t working correctly. Conscious retrieval is the most rewarding part of the cycle of remembering.
The memory process is one that continues to evolve as our lives grow and change. Through the process of encoding, storage, and retrieval, the human brain is able to access a lifetime of knowledge, experiences, and emotions.
We are able to clearly remember things like our child’s first steps, the smell of the ocean, or the way our first home looked because of the process of memory. Being able to access your story and experiences is an invaluable mystery of the brain that is essential to what makes us “human”.
Our memories shape what we are and are able to adapt as quickly as we do. Your memory takes all your experiences and shapes them into the story of you.