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Training Working Memory: Why and How

Make your working memory work for you.

Working memory refers to the memory you can consciously hold in your mind at any one instant—such as a phone number you just looked up. Most people can only hold about four totally independent items in their working memory.

Working memory relates to intelligence. The reason is that thinking involves streaming into the brain's "thought engine" chunks of information held in working memory. The working memory streams in, much like a Web video streams into your computer. The more you can hold in working memory, the more information the brain has to think with—that is, the smarter it can be.

IQ is not fixed. It improves dramatically in the early school years in all children. Moreover, a recent study shows that both verbal and non-verbal IQ can change (for better or worse) in teenagers.

Educators have known for some time that it is possible to train ADHD children to have better working memories, and in the process improve their school performance. The idea that working memory capacity might be expanded by training normal children has not yet caught on. Test-driven teaching in U.S. schools teaches students what to learn, not how to learn.

Researchers in Japan recently tested whether a simple working memory training method could increase the working memory capacity of children. While they were at it, they tested for any effect on IQ. Children ages 6-8 were trained 10 minutes a day each day for two months. The training task to expand working memory capacity consisted of presenting a digit or a word item for a second, with one-second intervals between items. For example, a sequence might be 5, 8, 4, 7, with one-second intervals between each digit. Test for recall could take the form of "Where in the sequence was the 4?" or "What was the 3rd item?" Thus students had to practice holding the item sequence in working memory. With practice, the trainers increased the number of items from 3 to 8.

After training, researchers tested the children on another working memory task. Scores on this test indicated in all children that working memory correlated with IQ test scores. When first graders were tested for intelligence, the data showed that intelligence scores increased during the year by 6% in controls, but increased by 9% in the group that had been given the memory training. The memory training effect was even more evident in the second graders, with a 12% gain in intelligence score in the memory trained group, compared with a 6% gain in controls. As might be expected, the lower IQ children showed the greatest gain from memory training.

I recently found a paper revealing lasting improvements in brain function were produced in healthy adults by only five weeks of practice on three working-memory tasks involving the location of objects in space, using a training program called CogMed. Similar results have been reported by other investigators.

Another study provides strong evidence that increasing adult working memory capacity will raise their IQ. Subjects, young adults were trained on a so-called dual N-back test in which subjects were asked to recall a visual stimulus that they saw two, three or more stimulus presentations in the past. As performance improved with each block of trials, the task demands were increased by shifting from two-back to three, then three to four, etc. Daily training took about 25 minutes.

The investigators found working memory training improved scores on the IQ test. Moreover, the effect was dose-dependent, in that intelligence scores increased in a steady straight-line fashion as the number of training sessions increased from 8 to 12 to 17 to 19.

Advances in this arena of raising IQ in teenagers and adults may come faster now that we have some many published reports that working memory capacity can indeed be expanded by training. The trick is in finding which approaches work best. Currently, we believe that working memory can be expanded by attentiveness training, music, and certain game environments. Actually, I believe demanding education can do the same thing.

Various techniques are reported in the research literature, and the best results seem to come from n-back methods. One study by Verhaeghen and colleagues show that memory span could be increased from one to four steps back with 10 hours (1 hr/session) of N-back training.

A whole cognitive enhancement industry is flourishing. The idea of brain fitness software is that playing mentally challenging games will make you smarter. This is not necessarily true. Several recent reviews suggest that such games do little. I can only recommend with some certainty those games that focus on expanding working memory capacity, and even here, one should not expect too much. I know about three such programs, MindSparke, Cogmed, and Jungle Memory. I have no personal experience or financial interest in any of these, but each has the potential to be helpful, especially in kids or adults with attention deficit.

Training Working Memory Can Be Fun

Biological reward comes from the release of the neurotransmitter, dopamine. Dopamine release is promoted by performing working memory tasks, which suggests that working memory tasks are actually rewarding. In the study of human subjects by Fiona McNab and colleagues in Stockholm, human males (age 20-28) were trained for 35 minutes per day for five weeks on working memory tasks with a difficulty level close to their individual capacity limit. After such training, all subjects showed increased working memory capacity. Functional MRI scans also showed that the memory training increased the cerebral cortex density of dopamine D1 receptors, the receptor subtype that mediates feelings of euphoria and reward.

Some games that are fun to play may also help working memory. The most obvious example is chess. To play chess well, you have to learn to expand working memory capacity to hold a plan for several offensive moves while at the same time holding a memory of how the opponent could respond to each of the moves. Not surprisingly there are studies showing that IQ scores can go up after several months of chess playing. Some schools, especially in minority schools in impoverished neighborhoods have seen marked improvements in school work by students who joined school chess clubs.

Students who make good grades feel good about their success. Likewise, people who are "life-long learners" have discovered learning lots of new things makes them feel good.

For numerous ideas on how to be a more effective learner, don't forget to check out my inexpensive e-book, Better Grades, Less Effort, available in all formats from


Alloway, T. P. & Alloway, R. G. (2008). Jungle Memory Training Program (Memosyne Ltd, UK).

Alloway, T. P. & Alloway, R. G. (2009). The efficacy of working memory training in improving crystallized intelligence. Nature Precedings. Htl: 1010/npre.2009.3697.1

McNab, F. et al. (2009). Changes in cortical dopamine D1 receptor binding associated with cognitive training. Science. 323: 800-802.

Verhaeghen, P., Cerella, J., and Basak, C. (2004). A working memory workout: how to expand the focus of serial attention from one to four items in 10 hours or less. J. Exp. Psychol, Learning, Memory and Cognition. 30 (6): 1322-1337.

More from William R. Klemm Ph.D.
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