The Neuroscience Behind Memories
By Maria Fujisawa
Memorization plays a key role in our lives, whether remembering where you put your keys or recalling information for a final exam. But how does our brain store and retrieve these memories? This article talks about the neuroscience behind memorization, the forgetting curve, and techniques to improve memorization based on neuroscience.
The Basics of Memory
The brain has 3 types of memory processes: encoding, storage, and retrieval. In the first step, encoding, the information is understood and enters the memory system. In this process, the sensory organs detect stimuli which are then translated into neural signals that are processed in the brain. In the second step, the information processed is first stored in short-term memory and then in long-term memory. Short-term memory lasts around 15–30 seconds and its capacity is limited only storing around 5–9 items. Long-term memory has a larger memory capacity and can store more information for longer periods of time, sometimes even a lifetime. Long-term memory can usually be categorized into 2 different types: implicit and explicit memories. Implicit memories are unconscious, usually procedural memories and explicit memories are declarative and semantic memories. The last step is retrieval, and in this step, individuals access the stored information, and can be categorized into recall and recognition. The prefrontal cortex plays an important role in this process.
The Neuroscience Behind Memorization
The main areas of the brain involved in memorization are the hippocampus, the amygdala, the cerebellum, and the prefrontal cortex.
- The hippocampus is located in the temporal lobe. The largest role the hippocampus plays is with holding short-term memories and transferring them to other areas in the brain for long-term memory. The hippocampus usually stores declarative memories such as facts, dates, and locations. Sleep plays an important role with transferring them to long-term memories.
- The amygdala is located in the temporal lobe, with one in each hemisphere of the brain, and plays an important role in processing emotional memories and also works with fear related memories.
- The cerebellum is located in the back of the brain above the spinal cord. It is involved in motor learning and contributes to episodic and procedural memories.
- The prefrontal cortex is located in the frontal cortex right behind the forehead and is important for retrieving memories.
Memorization can also depend on neurotransmitters and synaptic plasticity. Synaptic plasticity is the ability of synapses, the connections between neurons, to strengthen or weaken and change its strength. There are 2 main types of synaptic plasticity, short-term and long-term synaptic plasticity.
- Short-Term Synaptic Plasticity is temporary changes in synaptic strength that last a few minutes. These changes improve the transmission of signals between neurons.
- Long-Term Synaptic Plasticity refers to more permanent changes in synaptic strength that can last from hours to a lifetime. Long-term potentiation and long-term depression are two processes in long-term synaptic plasticity.
The Forgetting Curve
The forgetting curve is a concept introduced by a German psychologist by the name of Hermann Ebbinghaus and is a representation of how we forget information over time. His research showed that memory retention drops the most a few hours after gaining the information, and this can be seen from the steep curve right after the memory is gained in the figure below. The rate we forget at then gets less steep over time.
Techniques to Improve Memorization based on Neuroscience
- Spaced Repetition
One technique used to overcome the forgetting curve is to use spaced repetition. Ebbinghaus’ research showed that 50% of the information gained was lost in the first 30 minutes and after 24 hours, 70–80% of information had been lost. In order to overcome this, we could use spaced repetition to review immediately after class, 24 hours later, 1 week later, and 1 month later. Spacing out the review sessions helps with strengthening synaptic connections. There are stationery such as post it notes that use Ebbinghaus’ forgetting curve to encourage spaced repetition.
- Gamification
Another method is gamification, which, by integrating challenges, points and leaderboards, can boost dopamine levels — a neurotransmitter related to rewards and motivation that enhances learning and memory.
Best Apps for Memorization
Some apps that use this to enhance memorization are:
- Duolingo: a language learning app that uses gamification with features like streaks, daily goals, and leaderboards. These awards keep users motivated to practice regularly, reinforcing their memory through spaced repetition.
- Brainscape: an advanced flashcard app for learning through a confidence-based repetition algorithm. Unlike traditional flashcards, Brainscape gets users to rate how confident they are in each question on a scale from 1 to 5. Based on these ratings, the app adjusts the frequency of each flashcard’s review. Challenging concepts are shown more frequently, which optimizes learning.
