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.
http://www.psychologytoday.com/blog/memory-medic/201203/training-working-memory-why-and-how