Information Age Education
   Issue Number 41
May, 2010   

This free Information Age Education Newsletter is written by David Moursund and Bob Sylwester, and produced by Ken Loge. The newsletter is one component of the Information Age Education project. See and the end of this newsletter.

Working Memory—A Bottleneck in Your Brain

“The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them.” (Sir William Henry Bragg; British physicist and chemist who uniquely shared the Nobel Prize in Physics with his son, William Lawrence Bragg, in 1915; 1862–1942.)

This issue of the IAE Newsletter focuses on a human brain’s working memory. Working memory is used to retain and manipulate information during a short period of time. This ability underlies complex reasoning as well as other complex activities such as reading and understanding a sentence or a paragraph. Working memory performs executive functions, directing other parts of the brain to carry out various activities.

Torkel Klingberg (Ph.D. and M.D.) is a prolific researcher and writer on working memory and attention. He is a professor in cognitive neuroscience at the Karolinsky Institute in Stockholm, Sweden. Much of the content of this newsletter is drawn from his recent book (Klingberg, 2009).

A Very Simplified Brain Model

Here is a simplified model of a human brain. Senses such as sight and hearing bring in an immense amount of information. Some of this is ignored, some goes into your subconscious where it is processed at a subconscious level, and some goes into your working memory. What goes into your working memory depends considerably on your focus of attention. Working memory and attention are closely related.

Your working memory directs various other parts of your brain to process the incoming information that you are paying attention to. Much of this processing is done in a highly automated manner, using the procedural and episodic parts of your long-term memory. For example, with little conscious effort, you can interpret meaning from a simple sentence you are reading or a simple utterance you are hearing. However, if the sentence or utterance is long and complex, your working memory must remember pieces of it in order to give direction to the rest of your brain in extracting meaning from the various interrelated pieces.

Your brain contains a very large amount of long-term memory, but it has a very small amount of working memory. More than 50 years ago George Miller (1956) published his seminal paper, The magical number seven, plus or minus two: Some limits on our capacity for processing information. Since then there has been considerable research on this quite limited—seven plus or minus two or perhaps a little less—capacity of working memory.

In this simplified brain model, working memory is a bottleneck. If it were larger, our overall brain would be more capable. We would be able to focus attention on more different things at one time, and we would be able to direct active thinking on more different things at one time.


Multitasking has received a lot of attention in recent years. Multitasking is a situation in which attention and use of working memory are simultaneously focusing on two or more different tasks. A computer with two or more central processing units provides an analogy. Each CPU is able to function with considerable independence. Multiple CPUs make possible a certain type of multitasking and thus can increase the total productivity of a computer system. However, the hardware and software must resolve conflicts as different CPUs draw from and/or change the same pieces of information in the computer’s memory.

Part of the research on human working memory has focused on dual tasking—that is, working on two tasks at the same time. A variety of research tools have been developed to measure the effectiveness of working memory in directing overall brain processing on two simultaneous tasks. As an example, research has been done on the dual task of driving a car and using a cell phone. The driving task requires paying attention to visual inputs as well as sounds such as horns and sirens. The cell phone task requires paying attention to voice input and constructing responses to this input. If the cell phone is not a hands-free, voice activated system, using it can place still more demands on the phone side of the dual tasking.

Research—as well as lots of empirical data from traffic accidents—has provided good insight into how this set of dual tasks overloads working memory, leading to degradation in accomplishing each of the tasks. Degradation in the driving task leads to an increased chance of traffic accidents. Degradation in cell phone communicating may lead to poor communication.

Torkel Klingberg’s book explains how one’s total productivity can be increased by dual tasking. As a simple example, consider listening to music while reading a book. The music proceeds as a set pace, while you can increase or decrease your reading speed and glance back to a part previously read if you feel you have missed an important detail.

 If both the music listening and the reading are being done mostly for pleasure and entertainment, then this dual processing essentially achieves two in the time of one, so may increase your total pleasure. However, suppose that you are listening to the music in order to do a careful analysis of the style, quality of the music, quality of performance, and so on, while you are reading a textbook in order to understand and learn its content. Now you will experience degradation in accomplishing each task.

Torkel Klingberg’s book includes a brief discussion of multitasking capabilities of women versus men. He notes that the research literature suggests “no significant difference.”

The Flynn Effect

Quoting from Graham and Plucker (2002):

In his study of IQ tests scores for different populations over the past sixty years, James R. Flynn discovered that IQ scores increased from one generation to the next for all of the countries for which data existed. This interesting phenomena has been called "the Flynn Effect." Many of the questions about why this effect occurs have not yet been answered by researchers.

Torkel Klingberg’s book suggests that the increasing IQ is due to improvements in working memory. He argues that day-to-day life in our world has forced people to deal with more complex problems and with a greater volume of information. He also notes that some of our forms of entertainment have added to this increased demand on our working memory. For example, many movies and TV programs now include several different, interwoven strands in their stories. Many novels now include several different but interwoven strands. The stories and possible actions in computer games have become more complex. These and other changes over the past 70 years place increased demands on working memory. The plasticity of working memory leads to improved performance of working memory and long-term memory. This, in turn, leads to increased scores on IQ tests.

Of course, this past 70 years is not enough time for significant change to have occurred in the genetic makeup of the brain. So, in terms of nature versus nurture, the change is due to nurture. Note, however, the combination of epigenetics and cognitive development is a rapidly growing area of study and research. See  Research in epigenetics has shown us that environment can turn certain genes on or off, and such a switch in a gene’s activity can be passed on from one generation to the next.

Increasing Working Memory

It has long been known that a brain has considerable plasticity. Learning changes one’s brain. Active use of what one has learned preserves and strengthens the neural connections that constitute the learning.

Klingberg and other researchers have asked the question, “Does working memory have a type of plasticity so that it can be improved through appropriate interventions?” The book discusses two types of research results:
  1. A variety of working memory exercises have been developed that can be used to produce long-term improvements in working memory. This is true both in discipline-specific areas (for example, mental math problem-solving exercises leading to improvements in the math-oriented capabilities of working memory) and discipline-independent exercises leading to improvements that cut across disciplines. For example, see Posit Science at
  2. Drugs exist that improve executive and attentional functions of working memory processes. Examples include caffeine and Ritalin, as well as a number of drugs being developed to help deal with Alzheimer’s and other brain diseases. Ritalin is widely used with ADHD students, but it has an equal effect on the working memory of non-ADHD people.

Computers and Chunking

Working memory can only deal with about a half-dozen chunks of information at one time. However, a chunk can be quite a few individual pieces of information. For example, suppose you are math oriented and have memorized the value of pi to 10 decimal places.  A friend tells you his phone number is 314-159-2653. Aha! The first ten digits of pi. You just remember the chunk that your friend’s phone number is pi.

Suppose that you have a phone that stores phone numbers based on two-letter combinations.  The single chunk PJ (nick name or initials) is all you need to remember to access the person Paula Jones.

Now, carry that idea over to the very large number of problems that a computer can solve. What you need to recall from memory is a chunk that identifies a particular program. Suppose, for example, that you are analyzing a set of data that is in a spreadsheet on a computer. You need to figure out what these data mean. A relevant computer chunk might be “I know how to use the Excel spreadsheet program to graph a set of data.” You multitask as you continue to hold the overall problem in mind and at the same time tell the spreadsheet program to graph a specific part of your data.

In some sense, this graphing activity is like using the procedural part of your brain, except you are using the procedural part of a computer brain. You tell it to carry out a procedure that you “know” it knows how to do, and it does it. Contrast this with doing such a graphing task by hand. The by-hand approach can easily require all of the capabilities of your working memory and may well lead you to forgetting the original problem or why you are graphing the data.

Educational Implications

Research on brain plasticity and training the brain, research on various drugs, and steady increases in computer capabilities are giving us tools to help deal with the limitations of working memory. All three of these approaches are appropriate topics for teachers and their students to know about and for curriculum developers to take into consideration.


Graham, Charles and Plucker, Jonathan (2002). The Flynn effect. Human Intelligence. Retrieved 5/5/2010 from

Klingberg, Torkel (2009). The overflowing brain: Information overload and the limits of working memory. Oxford University Press. A number of Klingberg’s papers are available online at

Miller, George A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. The Psychological Review, 1956, vol. 63, pp. 81-97. Retrieved 5/2/2010 from

About Information Age Education, Inc.

Information Age Education is a non-profit organization dedicated to improving education for learners of all ages throughout the world. IAE is a project of the Science Factory, a 501(c)(3) science and technology museum located in Eugene, Oregon. Current IAE activities include a Wiki with address, a Website containing free books and articles at, and the free newsletter you are now reading.

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