Educators educating Educators

Jan 19

Types of Memory


Different types of memory systems

In their book Welcome to your Brain, Sandra Aamodt and Sam Wang write that we have 12 different types of memories or memory systems and all operate semi-autonomously. For instance, remembering your social security number is much easier than recalling how to ride a bike. The contrast proves a point: One does not recall how to ride a bike in the same way one recalls nine numbers in a certain order or one does not recall how to ride a bike in the same way one recalls numbers. The ability to ride a bike is independent from any conscious recollection of the skill. You were consciously aware when you were remembering your Social Security number, but not when riding a bike. Do you need to have a conscious awareness in order to experience a memory? According to Aamodt and Wang, no.


Types of memory

There are different types of memory: Short-term, Long-term (discussed briefly here but also under separate listing), Working, Explicit or Declarative, and Implicit or Procedural.


Short-term memory

Psychologists and researchers now believe that short-term memory is a collection of temporary memory capacities, each capacity specializes in processing a specific type of information, and each operates in parallel fashion with the others. As a result of this theory, short-term memory is now called working memory by some researchers/writers to reflect this multifaceted talent but I still consider them separate and distinct memories.

Short-term memory is placing menial demands on the brain for processing and is often described as storage-only tasks. For instance, one remembers a phone number and immediately forgets it after dialing the number.

There are two types of short-term memory: verbal short-term and visual–spatial. Verbal short-term is assessed using tasks that require the participant to recall a sequence of verbal information, such as a digit span and word span. Visual-spatial short-term memory tasks usually involved the retention of either spatial or visual information.

Long-term memory

Example of short & long-term memory.  Long-term memory is parking your car at the supermarket and short-term memory is remembering the quart of milk you intended to buy.  The difference between the two memories is how the brain stores the information.  Location of the car is stored in your long-term memory.  Note that no neurons in the frontal lobe are encoding the car’s location or are continually active therefore the memory becomes extinct.

The item you are looking for, the milk, is stored in your working memory.  This information is “online,” in that it is constantly in your consciousness in a way that corresponds to the uninterrupted activity of certain frontal lobe neurons.  How do the neurons remain active during this delay is a mystery.  One hypothesis, the presence of recurrent loops, neuronal networks that keep the activity going by stimulating each other.


Working memory

Working memory was a pioneering concept introduced by leading neuroscientists like Alan Baddeley and Patricia Goldman-Rakic, but it has since undergone many alterations.

Working memory is a busy, temporary workplace; a desktop the brain uses to process newly acquired information. It is the type of memory that enables you to spit back the last sentence of a conversation and is critical for performing some common operations in your head: adding numbers, composing a sentence, following directions, etc. The space devoted to that operation is recycled as soon as you turn to something else; therefore, the information does not become permanent memory.

Working memory is defined as the ability to keep information active for a short period of time based on continual neuronal activity. Working memory is used to control attention, to remember instructions, to keep in mind a plan of things to do, and to solve complex problems and is located in the frontal lobes.

Working memory is the ability to hold information in your head and manipulate it mentally. You use your workspace when adding up two numbers spoken to you by someone else without being able to use a pen and paper or a calculator or to remember a phone number and then mentally add the phone numbers.

Children at school need this memory on a daily basis for a variety of tasks such as following teacher’s instructions or remembering sentences they have been asked to write down.

Patricia Goldman-Rakic, a Yale neuroscientist, invented the Dot test and demonstrated information is retained in working memory when a certain pattern of neurons is continually active. Called delay-period activity, cells were active when a monkey looked at a dot it was to remember and continued to send an uninterrupted current of signals even when the dot disappeared. But when the monkey shifted its attention, the current stopped and the monkey would no longer be able to remember the information. She found this activity is located in the parietal and frontal lobes.

This process is much more dynamic than long-term memory in that it provides an immediate means of storage of information, since patterns of electrical activity can be established in a matter of milliseconds. However, it is a sensitive means, since the memory will be lost once the network is disrupted and the continual surge of activity is terminated.

In his book Brain Rules, John Medina describes working memory as a three-component model consisting of auditory, visual, and executive components. Auditory memory allows us to retain some auditory information, and is assigned to linguistic information, which is referred to as the phonological loop. Visual memory allows us to retain some visual information, and is assigned to any images and spatial input the brain encounters and referred to by Braddely as the visuo-spatial sketchpad. The prefrontal cortex, the central executive, is the controlling function, which keeps track of all activities throughout the working memory.

All have two important characteristics: limited capacity and limited duration. If the information is not transformed into a more durable form, it will soon disappear.


Tracy Alloway discussing Working Memory

At the April 2011 daylong symposium at Columbia University in New York City on the topic “Memory and Mind: Improving Memory and Achievement in the Classroom, Tracy Alloway, director of the Center for Memory and Learning in the Lifespan at the University of Stirling, United Kingdom, discussed the working memory and its relation to reading achievement. Alloway described working memory as the cognitive ability to handle multiple pieces of information simultaneous, such as to add numbers or pick out rhyming words. Alloway says “brain imaging research shows that during a working memory task, the prefrontal cortex is working hardest.”

Working memory skills develop through childhood, reaching adult levels around age 16. “But at any age there’s a huge range, Alloway said. “In a group of 10-year-old olds, some may look like average 5-year-olds, some like 15-year-olds.”

“The faculty is the foundation of learning,” she said: it determines the capacity to process information, follow instructions, and met classroom demands. Working memory predicts academic achievement far more robustly than IQ, and is less influenced by socioeconomic status.

For an example of the limitations of working memory, take the Stroop effect experience.

The famous "Stroop Effect" is named after J. Ridley Stroop who discovered this strange phenomenon in the 1930s. Here is your job: name the colors of the following words. Do NOT read the words...rather, say the color of the words. For example, if the word "BLUE" is printed in a red color, you should say "RED". Say the colors as fast as you can. It is not as easy as you might think!

Stroop Task Easy

Easy? Now try the next one. Warning, it will quickly become harder.

Stroop Task Hard1

The words themselves have a strong influence over your ability to say the color. The interference between the different information (what the words say and the color of the words) your brain receives causes a problem.


The Stroop effect experience is called interference. When you look at the word, you see both their color and their meaning. When these are in conflict, you have to make a choice. Because experience has taught you that meaning is more important than ink color, interference occurs when you try to pay attention to only color. Your working memory has to tell you to avert your attention from the meaning of the word and concentrate instead on the color.

The point being is that you are not always in complete control of what you’re paying attention to.


Although I have never tried it, I think that this puzzle would be easier for a very young child than for older children or adults.  A child who has learned the names of colors but cannot read probably would have no problem with the Stroop effect experience since the words do not have any meaning, the child’s attention would be on the color of the word.


Explicit/Declarative memory

The second type is what we most commonly associate with “memory”. This is long-term or explicit/declarative memory, and is composed of all the facts, figures, and names you have ever learned. All of your experiences and conscious memory fall into this category. Scientists differentiate between two types of explicit/declarative memory. Semantic memory is about information not related directly to people, locations, or time: it’s generalized or factual information without (necessarily) specific content, such as the multiplication tables. Episodic memory is about experiences relating to the self and it is the very heart of autobiographical memory, which forms the foundation of the self and self-awareness. According to Judith Horstman in The Scientific American Day in the Life of Your Brain, the hippocampus is responsible for episodic memory, and the surrounding cortex controls semantic memory. Although no one knows exactly where this enormous database is stored, it is clear that the hippocampus is necessary to file away new memories as they occur.

Implicit/Procedural memory

The third type of memory is implicit/procedural memory, and is probably the most durable form of memory. These are actions, habits, or skills that are learned simply by repetition. Examples include playing tennis, playing an instrument, solving a puzzle, etc. The hippocampus is not involved in procedural memory, but it is likely that the cerebellum plays a role in some instances.


“If we can control the attention of the child, we solve the problems of education.” Maria Montessori

This month Ed Tip will examine how to improve students' learning by activating their attention.