A brief explanation of the cognitive and neuroscience
We have an excellent neuroscientific understanding (1) of how long-term memories are stored and made more robust by retrieval practice. Explicit memory represents the memories and knowledge that we can consciously retrieve.
The subset of explicit memory, known as semantic memory, is the long-term memory of facts and concepts. These memories are stored in the synapses of a relatively small collection of neurons that may be close together or dispersed throughout the neocortex of our cerebral hemispheres.
These neuronal collections, which many scientists call engrams, are activated when we retrieve that long-term memory into working memory. When we retrieve this memory, the engram is activated. Because of our brain’s astonishing neuroplasticity, the synapses in that engram are strengthened, and even more incredible; additional synapses may develop. We have been able to directly image this effect (2) in living lab animals. Whenever you retrieve a memory, you make it more easily retrievable in the future. This is a prime reason why retrieval practice strengthens our ability to recall that piece of knowledge.
There is however another effect to consider. Each time we retrieve a memory, we do so in a unique context. This context is a combination of the place, time, emotional state, other thoughts and events, current sensory inputs, and many other potential parameters.
When we consciously retrieve a memory, the unique current context may create or activate engrams that overlap the engram of the memory we’re retrieving. After all, a neuron may have many thousands of synaptic connections. These create opportunities for a neuron to participate in many different engrams. This explains why one thought leads to another. Our brains think by association. It’s the embodiment of the old neuroscientific maxim, “neurons that wire together, fire together.”
Every time you retrieve a memory, the current context may create a new pathway for retrieving that memory in the future. The more routes we create through retrieval practice in unique contexts, the easier it’ll be in the future to bring that memory into consciousness on demand.
I would be remiss if I didn’t mention that there is another important type of memory called procedural memory which with worthy of a separate discussion, but we’ll leave that for another day.
Retrieval practice combined with spaced repetition are proven power tools for learning and helping us to remember what we’ve learned.
iDoRecall takes spaced repetition flashcards to the next level by enabling you to link each flashcard to the exact location where you learned that piece of knowledge. This makes it easy to refresh your memory, if needed, during retrieval practice.
iDoRecall has created comprehensive linked flashcard sets covering the essential facts, concepts, and formulas in over forty OpenStax textbooks. When you click the source button, a PDF of the textbook will open at the exact relevant location. Students, educators, and schools can use these flashcards for free.
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(1) Josselyn S. A., & Tonegawa S. (2020) Memory engrams: Recalling the past and imagining the future. Science, 367(6473). https://doi.org/10.1126/science.aaw4325
(2) Roy, D. S., Arons, A., Mitchell, T. I., Pignatelli, M., Ryan, T. J., & Tonegawa, S. (2016). Memory retrieval by activating engram cells in mouse models of early Alzheimer’s disease. Nature, 531(7595), 508-512. https://doi.org/10.1038/nature17172