Learning and Memory: How Do We Remember and Why Do We Often Forget?

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please support us with a print or digital subscription!)


While memory cannot occur without learning, once information has been learned, our memory may allow the learning to decay. Occasionally, memory will unintentionally play a bit loose with the truth regarding what was previously learned.

Emotions can be a catalyst or an impediment to learning. It has been estimated that 95 percent of our reactions are unconsciously driven by the amygdala and only modestly impacted by the executive centers of the cerebral cortex. Although ours is generally considered a rational brain, it is an emotional brain, where feelings receive first priority. A student who is upset is one who cannot learn and will not remember content information well during assessment.

In school, mere exposure to content information (lecture, text, etc.) is no guarantee that it will reach the personal/emotional threshold of “personal importance” to the learner, where encoding the information for permanent memory storage is deemed warranted. What students encode depends on what they are paying attention to at the time. Although we often wonder why our students forget important lesson content, the bigger problem is, Was it ever encoded for memory?

An important distinction has to be made between listening and remembering. Teachers often feel obligated to clarify what indeed is important, at least for testing purposes, because students cannot “essentialize” (a term coined by Dr. Robert Grant), separating the crucial from the tangential.

Several connected brain regions play key roles in memory formation, including the thalamus, amygdala, hippocampus, and cerebral cortex. It is the interaction of nearly all parts of the brain that allows for the construction of our memories.

The amygdala and the hippocampus are vital to learning in the classroom:

  1. The stronger the emotions connected to an experience, the stronger the subsequent memory.
  2. The neural networks most important emotionally to a student are bathed with neuro-nutrients, enhancing memory formation and retention.
  3. Learning experiences become more memorable when social-emotional memories are part of the learning event, which is why cooperative learning is such a powerful memory-enhancer in schools.

The hippocampus plays a crucial role in forming and storing our memories of facts and events. Initially, short-term memories are briefly stored in the hippocampus, prior to being transferred to other brain regions where they are consolidated with prior knowledge into long-term memories. While persistent stress can damage hippocampal brain cells — patterns, emotions, relevance, context, content, and sense-making boost attention, memory formation, and recall. Collectively, they can determine what information reaches permanent memory storage. As Stanford Ericksen summarized the requisite emotional element in learning, “Students learn what they care about and remember what they understand.”

When information is determined to have potential long-term value, the hippocampus links the significant elements of that event or experience together, forming a permanent memory. Creating, storing, retrieving, and using our spatial memories and episodic memories are characteristic brain capacities made possible by the hippocampus. When we daydream, the hippocampus is strikingly active. Brain-imaging studies have shown heightened activations in the hippocampus not only when we are recalling memories but also when we put the mind on “wander and wonder.” This has important implications concerning creativity and innovation, which are based on our ability to manipulate and expand on stored factual information.

Upon hearing a new girlfriend’s birthday, that information enters her companion’s short-term memory. As the relationship progresses, this short-term memory is converted into permanent memory through the process of consolidation. Emotional memories are among our strongest and easiest to recall — an A on a final exam, our high school and college graduation ceremonies, our senior prom date, etc. As a result, neurodegenerative diseases including Alzheimer’s are extremely terrifying, since the disease causes us to forget critical information identifying who we are, who we love and who loves us most — our emotional connections.

When a noteworthy personal date is shared with a loved one — e.g., an anniversary — that random day is tagged in the vast chronological time scale and is emotionally coded, making it a prime candidate for permanent memory storage. Those dates of significance require regular attention, mental rehearsals and reinforcement to maintain our ability to recall them effortlessly. Classical conditioning would suggest that a secondary motivation exists—punishment associated with any tendency to forget those dates—which increases the probability that they will enjoy flawless recollection.

Information that cannot be successfully stored by the hippocampus cannot be remembered or subsequently retrieved. Due to the manner by which elements that compose a memory get distributed throughout the cortex, long-term memories are generally stored safely. Damage to the hippocampus renders the formation of new memories virtually impossible.

Emotional experiences (both positive and negative) enjoy the highest probability of reaching permanent memory storage. It is the amygdala-hippocampus connection that fosters the development of our most memorable moments in life. In the classroom, emotions determine what students pay attention to, which impacts what students will later remember.


The complex human brain has an extensive repertoire of different types of memory strategies that are deployable for varying lengths of time on special occasions with distinctly different purposes and outcomes driven by multiple memory systems. (See: “A Dictionary for Types of Memory.”)

If new connections are not strengthened by active usage, they soon disintegrate. The more frequently a given network of neurons fires together, the greater is the likelihood that they will hardwire together permanently, increasing the likelihood that they will fire in unison in the future, according to Donald Hebb, the father of cognitive neuroscience. But it can take as many as six exposures before new information enters into permanent memory.


Reading does not necessarily lead to learning. Doing, engaging in two-way discourse and thinking will aid learning and memory; however, when students are doing, playing with objects, exploring, experimenting, talking, drawing, writing, listening, reading, speaking, applying, and reflecting on all of these, neural pathways for learning develop inside the brain. The distinguished educator John Dewey said, “We don’t learn from experience, we learn by reflecting on it.”

Important distinctions must be made in memory formation between what one understands versus remembers; recognizes versus recalls; remembers versus can reproduce; remembers versus knows how to apply.

Although most adults can recall times in school when a greater emphasis was placed on whether we remembered the facts than on whether we understood how to use them intelligently, memorizing lists of facts and information is not an adequate approach to 21st-century learning. Rote learning for the Industrial Age differs significantly from dynamic memory, where learners examine what they know as they think about the quality of their own thinking and decision-making.

Perhaps the most useless of all academic exercises is memorizing terms from the dictionary. Instead, schools should use the SCREAMS approach to build a firm foundation for student vocabulary, by:

  • Saying/pronouncing key vocabulary words
  • Concept mapping or word webs
  • Reading words in context
  • Extracting personal meaning
  • Active learning experiences where students use the new word frequently
  • Memory formation (sense-making) based on utility
  • Self-monitoring for new opportunities to use the newly learned word

Our memories receive varying but focused treatment depending on the nature of the memory. A working memory is deliberately short-term, with limited recall capacity, because its “useful life” is brief by deliberate design. When we dial 411, all information reaching the auditory cortex and the hippocampus must be meticulously recalled with detailed precision. However, its utility is short-lived, with a correspondingly short-lived memory record (less than 30 seconds) established for the phone number. We are obligated to rehearse that number silently or aloud to retain it in working memory long enough to dial it.

Abbreviated memories of this genre typically have a capacity of seven items +/- two items. Thus, we can easily recite the seven days of the week, a seven-digit telephone number, Snow White’s seven dwarves and the seven deadly sins. Yet, on average we can remember no more than seven of the biblical Ten Commandments, but seldom all 10. By grouping information into chunks, creating mentally bite-sized smaller groups of the larger units, recall improves impressively. A telephone number of 4082669497 is easier to remember as (408) 266-9497, by combining the random numbers into small groups. It is no surprise that math problems with a two-digit divisor and a three-digit dividend requiring 27 memorized steps are often met with failure and frustration.

(Editor’s note: This article is from a past issue of Brain World magazine. If you enjoy this article, please support us with a print or digital subscription!)



  1. I’m not close to the same level as the researchers but I just had a couple thoughts, as a generally intelligent person.
    First I wish I could sit down with one of the people doing this research for even an hour to be able to ask them some things I don’t get or don’t believe or disagree with because I’m sometimes skeptical. Anyone know a memory specialist willing to talk to a stranger about their work?
    What makes me unable to believe some of the conclusions made is that a lot of it seems to come from analysis of certain cells and/or mice involving shining light in certain areas. It just doesn’t seems like the right thing is being observed or not the right way. As I said, I don’t know and may be 100% wrong but my gut tells me it’s not accurate enough to say it’s known how memory works.
    If possible, wouldn’t a more accurate test be to give a number of subjects the same input simultaneously and monitor each’s brain as it is absorbed? Then to ask each questions about the input and see what part/s become active and perhaps see what is missing when one can’t remember and another can immediately? It just doesn’t seem possible to follow individual cells traveling the speed they do. And if it’s not actually within the brain at the time or part of a simulation, I don’t think it will give the answers we’re after.
    Right now I’m imaginging a line of people sitting in recliners with electrodes all over their heads watching a single screen. I’ve had an EEG before and given plasma/blood so those memories are now playing but only snippets because who remembers every detail of everything? Oh yeah, some do. They should be added to the test for comparison, and… done.
    The last thing I would love to discuss if I ever get the chance is that I’ve heard that though we cannot recall every detail of events, our brain is actually taking in every sound, smell, sight, feeling and taste every second of every day. It’s simply not necessary for us to retain all that but it happens. Sleep is when the brain is able to go through and according to priority and patterns of recall it has learned along the way it sorts it all with the most likely to be needed items more readily available. Personally, I think when you can’t put a name to a face, don’t remember who was with you certain times, identify a scent but know it, these are just things misfiled as less important based on every prior memory you wanted to access. But technically the info is there.
    Sorry for the length, thanks if you made it through. I’m just fascinated by things like this and haven’t found the answers yet, if they are out there at all. I hope so. Feel free to email and learn me somethin’.

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