Ever lose your car keys? Have trouble remembering a word that feels like it’s on the tip of your tongue? Forget why you walked into a room? Memory can appear simple, like a videotape in your head that either turns on or doesn’t. You either remember or you don't, right? Not so much. In reality, memory is a wildly complex process that experts are still figuring out. But diving into how memory works and what current research is discovering can help you better understand how to make memory work for you. So, how does memory work?
How Memory Works: The Basics
Neurons and Synapses
At its most basic level, memory is about neurons and synapses. Neurons are nerve cells in the brain, and synapses are the junctions between neurons. The synapses carry signals from neuron to neuron. These are the pathways that can form memories.((Matlin, M. W. (2005).
Cognition. Crawfordsville: John Wiley & Sons, Inc.)) Neurotransmitters are chemicals that allow the neurons to send their signals through the synapses. So, chemicals in your brain trigger neurons to signal other neurons through their synaptic connections.((Stierwalt, S. (2016, November 19).
How memory works and 6 tips to improve it. Retrieved September 23, 2019))((Texas A&M University. (2016, May 17).
How does memory work? ScienceDaily. Retrieved September 23, 2019)) Neural connections aren't forever. The brain is constantly changing because your neural pathways are constantly forming and eroding, weakening and strengthening.((Sternberg, R. J. (1999).
Cognitive psychology (2nd ed.). Fort Worth, TX: Harcourt Brace College Publishers.)) If you want to increase the chances of remembering something, a good start is to beef up these pathways. In short, use the neural pathway so you don't lose them.((Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information.
Psychological Review, 63 (2): 81–97.))
1. Encoding
Before a memory can form, we first have to sense something. Let’s say we see a table or smell a flower. This is called sensory input. Encoding is the process of changing that sensory input so that it can potentially be stored later as a memory. There are three different ways encoding happens:
visual, acoustic, and semantic. Visual encoding is when the sensory input is being changed into a picture or visual representation. Acoustic is auditory and semantic involves words. For example, when you are studying a picture, you are using visual encoding. When you say someone’s name over and over to try to remember it, you are using auditory encoding to try to store that name in your memory. And when you write down ideas in your own words, you're activating semantic encoding.
2. Storing
After a sensory input gets encoded, the brain has two major ways of storing that encoded information as memory. The first is in
short-term memory. Short-term memory occurs predominately in your prefrontal cortex, which is behind your forehead. The brain can only hold a limited amount of information in short-term memory before it is either turned into long-term memory or forgotten. The other major category of memory storage is
long-term memory. Long-term memory requires short-term memories to be consolidated. This happens when neural pathways are strengthened by an increased number of signals, especially in the brain region called the hippocampus. There are many types of long-term memory including procedural, declarative, implicit, and explicit. Procedural memory does not require us to consciously recall information. Think about riding a bike, procedural memory is a kind of implicit memory, which means we don’t have to consciously recall anything. On the other hand, declarative memory is when you can consciously recall facts or figures. Declarative memory is a kind of explicit memory, which means we do consciously recall information.
3. Retrieval
The final stage in memory formation is retrieval. Retrieval is when you recall information through those neural pathways that previously encoded and stored information. The interesting part of retrieval is that it is never exactly the same as when the input was encoded or stored. Retrieval is like a reconstruction of what was encoded and stored. It is not at all like a video recording that can be played and replayed, and stays the same each time. The act of retrieval is actually a creative act. The brain has to sift through all kinds of neural noise to recreate or recall the memory. So, much of our accuracy at remembering really depends on what competing, neural pathways are also signaling. Scientists have recently discovered that retrieval also depends a great deal on what the brain has forgotten.((Science Mag:
REM sleep–active MCH neurons are involved in forgetting hippocampus-dependent memories))
The Importance of Forgetting
Recently, scientists have discovered that neurons in the hypothalamus clear out old memories during sleep.((The New York Times:
Scientists Identify Neurons That Help the Brain Forget)) Some scientists now think that forgetting things is an active mechanism in the brain that actually helps us clear out less important information in order to better retrieve the important ones.((Berry, J.A., Cervantes-Sandoval, I., Nicholas, E.P., & Davis, R.L. (2012, May 10). Dopamine is required for learning and forgetting in drosophila.
Neuron, 74 (3): 530-542.)) Scientists discovered a group of neurons in mice’s brains that were active during R.E.M. sleep.((Izawa, S, Chodhury, S., Miyazaki, T., Mukai, Y., Ono, D., Inoue, R., Ohmura, Y., Mizoguchi, H., Kimura, K., Yoshioka, M., Terao, A., Kilduff, T., & Yamanaka, A. (2019, September 20). REM sleep-active neurons are involved in forgetting hippocampus-dependent memories.
Science, 365 (6459): 1308-1313.)) These neurons were suppressing other neurons in the hippocampus, essentially clearing out some memories during the dream stage of sleep. They think this might be why people struggle to remember their dreams. There’s an active forgetting process occurring at that time to clear out some of the neural pathways, thereby clearing out some of the neural noise in the brain to make retrieval of important memories easier. Now that we’ve answered, “How does memory work,” you can start to make your memory work better for you.
How You Can Make Your Memory Work for You
1. Practice Different Encoding Strategies
Because the brain encodes inputs in three different ways, experiment with all three (visual, auditory, and semantic) to see which is more effective for you personally. Everyone's brain is different, there are lots of different types of memory, and each brain has billions of neurons, so it makes sense that encoding isn't going to be the same for every person and in every situation. So, mix it up. Draw a picture, repeat something aloud, and put it in your own words. Many people think auditory encoding is crucial for long-term memory, so try to turn information into a song or repeat something aloud numerous times to consolidate information into long-term memories.
2. Don’t Just Remember with Your Brain
Some memory happens in the body. Think procedural memory. So don’t forget about using your whole body to try to remember better. Get out of your chair. Walk around. Dance while reciting the information you want to remember.
3. Pay Closer Attention to Sensory Inputs
Memory starts with sensory inputs, so the more you tune in to your environment and the people around you, the more likely you will remember things. Make things important. Pay attention. Be mindful of what’s going on around you. Memory starts with perception, so put the phone down and give your brain some concentrated inputs.
4. Write Stuff Down
Memory is imperfect and requires encoding, so another way to make memory work for you is to write things down. Writing is a kind of semantic encoding but it’s also an active, embodied experience, which will get more parts of your brain on board.
5. Get Your 8 Hours of Sleep
Since some scientists now think clearing out old pathways is important to the retrieval of other memories, you need to give your brain the chance to clear out some of that noise. Get a full night’s rest, so that you can have some solid rounds of R.E.M. sleep. This gives your brain a chance to clear out unimportant pathways and boost retrieval.
6. Use It or Lose It
Memory is an active process, so practice that process regularly. Strengthen your pathways to have a better chance of remembering the things you want to remember.
7. Get Some Exercise
Move your body and get some oxygen flowing into your brain. Some studies show that exercise helps strengthen your memory.((Harvard Health:
Exercise can boost your memory and thinking skills)) It reduces inflammation in the brain, which enhances your neurons’ ability to create their pathways.
8. Know That Memory Is a Creative Process
Now that you know that memory isn’t just a perfect recording, use that to your advantage. Practice your retrieval, but be open to other people’s interpretations of the past. Memory is imprecise. Be okay with the imprecision.
Final Thoughts
How does memory work? Memory starts with sensory inputs then moves on to encoding, storing, and retrieval. The very act of remembering something hinges on the strength of our neural pathways and the amount of competition between other pathways. The good news is that the brain is plastic, meaning it changes. It changes the most when we are young, but it’s encouraging to know that throughout our lives, it never stops changing. We are constantly forming, reforming, and eroding pathways in the brain. Which pathways you deem important and which you focus on will determine how your brain remembers in the future. So, be conscious and intentional about your pathways. Be mindful of your sensory inputs and then intentional in how and what you encode and then what you consolidate into long-term memory. And use it or lose it. Memory is active and complex, and the more we practice and get to know it, the stronger and healthier our pathways will be in the future.
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