By Jeffrey MacCormack and Ian Matheson
Even though we’ve known for some time that working memory and learning disabilities (LDs) are related, we still don’t fully understand their relationship. Working memory is our ability to store information temporarily while our brain is busy with a different task. We use our working memory to learn language, solve problems, and complete countless other tasks. Our capacity for working memory is limited and if we break our attention or overload the memory system, we can lose some of the information stored there. For students who have working memory deficits, such as those with LDs, losing the information that was stored in the working memory can be a huge obstacle to learning.
What is Working Memory?
Working memory is a theoretical model (Baddeley & Hitch, 1974) that explains how we can store information for the short-term without having to put it into long-term memory and decide which information to encode to long term memory. Keeping information in our working memory is incredibly important when learning new concepts. For example, while students may have the steps of long division recorded in long term memory, they may also need to store the instructions of the teacher while solving a math problem.
Working memory is similar to our concept of short term memory, but it is different in important ways. Working memory is the capacity to store information while doing other cognitively draining tasks (Gathercole, Alloway, Willis, & Adams, 2006). When researchers want to measure working memory they may use a task such as asking a student to evaluate the meaning of a series of sentences and remembering the last word of each sentence (e.g., Daneman & Carpenter, 1980). According to Baddeley’s model, there are four components of working memory that all have separate jobs. Three of the components are “slave systems” in which we automatically and temporarily store sound and image sensory information. The fourth system, the central executive, is different from the slave systems because its use is effortful and strategic.
Phonological loop. Have you ever had to remember a phone number for a few seconds while you searched your desk for a pen to write it down? You likely repeated the number to yourself until you could jot it down. When you keep auditory information in your mind, you use your phonological loop to retain the order of the phone digits. When we hear words spoken, we can hold the sound of the words in a part of our working memory called the phonological store. Usually we can only keep the sound-based information for a few seconds. If we need to remember something longer than a few seconds, the articulatory control process works as an inner voice, repeating the information on a loop.
Visuo-spatial sketch pad. Not only do we store temporary information in sound form, we also store visual and spatial information to our working memory in our visuo-spatial sketchpad, also referred to as visual-spatial sketchpad (Baddeley & Hitch, 1974). The visuo-spatial sketchpad updates and accesses information in our long-term memory as well, which makes it perfect for remembering the layout of your classroom and the number of bushes in the backyard. If you were asked how many cupboard doors you have in your kitchen, you would likely create a mental image of your kitchen and then count the doors.
Episodic buffer. The episodic buffer works as a back-up memory system that can store both visuo-spatial and phonological information in “episodes” of information.
Central Executive. The three slave systems of the working memory (phonological loop, visuo-spatial sketch pad, and episodic buffer) are all controlled by the central executive. The central executive decides which information is more important for working memory. Baddeley (1986) explained the role of the central executive by comparing it to a boss of a company. Like a boss, the central executive collects information from various sources, determines which tasks require the most attention, and allocates resources as required.
Helping Students with Reduced Working Memory
Two approaches have been used to help students who experience working memory delays. The first strategy, using training to improve working memory in students, has not seen much success in the research literature. The second approach, creating learning environments that reduce the strain on students’ working memory, has been widely adopted to help students with LDs.
Improvement through training. While some training interventions have led to some short-term improvements in verbal working memory, visuo-spatial working memory, and word decoding (outlined in meta-analysis by Peijnenborgh, Hurks, Aldenkamp, Vles, & Hendriksen, 2015), those improvements do not last long and are not easily transferred to other learning situations (e.g., Melby-Lervag & Hulme, 2013). For example, computer training programs, such as Robomemo provides working memory practice for 35 minutes a day for six weeks and has shown some ability to improve players’ working memory (Klingberg et al., 2005). Outside of the limited gains through direct training, working memory is generally considered to be a constant trait that is not easily improved through intervention.
Reducing working memory load. Using by-pass strategies to reduce the load on working memory is more often chosen to alleviate students’ difficulties. Gathercole and Alloway (2008) recommend that teachers take a multi-step approach to supporting students with working memory deficits.
- Recognize the problem. Look for signs that the student is having difficulty maintaining ideas or instructions in mind.
- Conduct an audit of the working memory loads. For example, consider how many instructions you give the students before sending them off to work. If you find that the students have to process a lot of information, you can reduce the complexity of the task and eliminate meaningless materials.
- Repeat and emphasize the important information. Other students can be recruited as memory guides. Using wall charts, personalized dictionaries, and memory cards can help students with working memory issues because the student can outsource the memory requirements. Anchor charts (e.g., How-to charts), success criteria (e.g., Did-I? checklists), and bump-up walls (e.g., Where I Am And Where I Am Going charts) help to reduce the extraneous load and allow students to access guiding information without having to search long term memory.
- Help the student to self-advocate. It can be disorienting to lose instructions in the middle of a task, but students who have poor working memory skills need to be able to take steps to help themselves, such as taking notes, asking for help, staying organized, and putting information into long-term memory.
Dunstan may not have been a great speller, but everyone knew he was an expert at Minecraft; he absolutely loved playing the videogame. He constantly talked about building strategies and even watching YouTube videos about how to play. To entertain his friends, he told stories about adventures in the Minecraft world, battling Ender Dragons and sighting Herobrine, which he easily made up on the spot. It was no surprise that when Dunstan was asked to write a story in class that he decided to write it about his favourite video game. “Remember to include three characters, a point of tension, and an ending that resolves the problem,” his teacher told the class. As Dunstan started writing, he was surprised to find the process to be really difficult. He knew what he wanted to write, but trying to fit his ideas into the structure of a story was a terrible chore. He couldn’t concentrate or keep the story ideas in his head. He could see the story happening in his mind, but felt helpless to write it down. Every time he started on a sentence, his mind went blank and he had to start again. After the writing period, he looked at his page. He had only written the title, his name, and three unfinished sentences.
For students like Dunstan, who have difficulty keeping phonological information in their working memory, organizing ideas into words can be a challenge. As the working memory gets overloaded, the student will lose the crucial information that is needed to complete the activity. Research shows that it is very difficult to keep two different pieces of information in the phonological loop or the visuo-spatial sketchpad. In Dunstan’s case, he lost the storyline he was trying to write whenever he tried to sound out the words he was writing. Providing information on graphic organizers can help students like Dunstan because by outsourcing some of the thinking to the graphic organizer, Dunstan doesn’t have to store as much information in his working memory.
In grade 6, Catrina had to switch from graphic novels to chapter books because her mother thought chapter books were more age-appropriate than “those comic books.” Catarina didn’t mind. She didn’t think it would actually be that big of a deal. Her favourite graphic novel series was also available in chapter book form. She was able to put down her last graphic novel and pick up the chapter book that was next in the series. The problem is that when Catrina started reading the chapter book, she had a really difficult time making sense of the paragraphs. The long lines of straight black text seemed to wobble on the page and by the time Catrina got to the end of the line she lost the train of thought. She found herself re-reading the lines and not making any progress down the page. She had hardly finished the first few pages and she was exhausted and her eyes hurt.
Considering how important letter sounds are to the task of reading, it may not be surprising that the phonological loop is considered closely related to ability to read. Students who score poorly on phonological loop tasks generally have difficulty learning to read. Reading difficulties may also be related to poor visuo-spatial recall, as poor readers are also less able to recall visuo-spatial information than typical readers (Swanso, Cochran, & Ewers, 1990). For students like Catrina, reading problems are not caused by reduced reading skill or lower intelligence. Teachers can help students like Catrina by reducing distractions, guiding the reading, and providing assistive technology solutions.
Keone loved Fridays. Every Friday afternoon, her class received the Friday Math Problem on little sheets of blue paper. The best part was that once the question was solved, the students were allowed to go outside for an early recess. Keone took special care to read the question off the paper and answer as carefully as possible. Keone was usually one of the first students to solve the math question and go outside. On this Friday however, there was no question on the blue piece of paper. Instead the teacher read the question out loud, “The store manager bought 18 litres of floor cleaner. Each litre of cleaner will clean 40 square metres of floor. The floor of the store is 56 square metres…” The question seemed to go on and on. Keone wrote down the number 40 but she wasn’t sure if that was the amount of floor or the litres of cleaner. The teacher read the question again, this time slowly, but again Keone couldn’t follow along. Eventually the teacher came over to help Keone finish, but by that time the rest of the class was already outside.
For students who have a hard time keeping strings of information in their working memory, having questions read out loud can be very difficult. Even for Keone, who could usually solve the math problem quickly, not being able to organize the information meaningfully in her mind meant that she was less able to solve the problem. Helping students with working memory deficits can be frustrating for teachers who may perceive that the learners are absent-minded, describing them as “zoning out.”
It is not clear which component of working memory is responsible for math-related LDs. Some research points to the phonological loop as the root of math-related LDs (e.g., Dark & Benbow, 1994), while other research points to the visuospatial sketchpad (e.g., Siegel & Ryan, 1989). There is also some evidence that suggests that both the phonological loop and visuo-spatial sketchpad are affected by diminished central executive system (e.g., Gathercole & Pickering, 2000).
As a teacher, helping Keone on Math Problem Fridays may be as simple as providing the option of a written question. Research has shown that having another student paraphrase the question can help students like Keone process the information. Being unable to receive verbal instructions will be a bigger problem later in life when Keone is at work and has to process her boss’ instructions for the shift. By that time, hopefully Keone will have developed some self-advocacy skills such as asking for the instructions on paper or keeping a notepad with her at all times.
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Jeffrey is a PhD student at the Faculty of Education, Queen's University, with a focus on cognition. He is a teacher certified by the Ontario College of Teachers with 9 years of experience teaching elementary school. He worked as an instructor at Queen's University and has taught and authored online courses for educators. He is currently conducting research on several topics including: learning disabilities, autism, emotional well-being, and youth development.
Ian Matheson is a graduate student in the PhD program in Education at Queen's University with a focus in Learning and Cognition. Along with teaching and research experience at Queen's University, Ian also has experience as an occasional teacher with the Limestone District School Board in the elementary division.