Tuesday April 29 2008
Sudoku helps mental improvement at similar tasks
“Mind games may improve our performance at work”, reads the headline in The Times today. The newspaper reports that a new study has shown that volunteers who took part in “rigorous exercises designed to tax their mental agility… stimulated problem-solving abilities in the brain that can be applied to a variety of circumstances.” It says that other forms of mental exercise such as Sudoku or crosswords “have limited value because they help mental improvement only at similar tasks”,
This story is based on a non-randomised controlled experiment using student volunteers to look at the benefits of a particular form of working memory training on “fluid intelligence” – the ability to solve new problems. Because the groups in this study were not randomised, it is not clear whether all of the benefit seen was due to the training received. More importantly, the study did not assess whether the training had any effect on their jobs or studies.
Although this study by itself does not prove that brain training improves intelligence, other studies have suggested that keeping the mind active may have various benefits, including a reduced risk of dementia. In general, it would seem sensible to keep the mind as well as the body active. There are many ways to do this, and it certainly has not been proven that the only way to do this is by using a computerised training program.
Where did the story come from?
Dr Susanne Jaeggi and colleagues from the Universities of Michigan in the US and Bern in Switzerland, carried out this research. The preparation of the paper was supported by Swiss National Science Foundation Fellowship, the National Science Foundation and the National Institute of Mental Health. It was published in the peer-reviewed scientific journal: Proceedings of the National Academy of Sciences of the USA.
What kind of scientific study was this?
This was a non-randomised controlled experimental study looking at whether working memory training affected fluid intelligence. Fluid intelligence was defined as the “ability to reason and to solve new problems independently of previously acquired knowledge”.
The researchers enrolled 70 healthy student volunteers at the University of Bern (average age 25 years). Thirty-five of these students were given working memory training and 35 students matched to them were not given any training (controls). Students in the training group were split into four groups and given different amounts of training: eight days, 12 days, 17 days or 19 days. Students trained daily for about 25 minutes. Training group participants were given standard tests of fluid intelligence before and at least one day, but no longer than two days, after completing training. Their matched controls were given the tests at the same time intervals.
Training involved looking at a computer screen while listening to a simultaneous recording. The computer screen showed a series of different spatial positionings of a white box on a black screen (eight possible positions) while a letter (one of eight consonants) was read out over the earphones every three seconds. The volunteer had to click a button if the position of the white box or consonant matched what they heard or saw a certain number of screens ago (e.g. two screens ago). Once their performance improved, the number of screens they had to remember was increased (i.e. increased to three screens ago, then four, then five and so on). If their performance worsened, the number of screens they had to remember was reduced. Each training session included 20 blocks of this test.
Different fluid intelligence tasks were used before and after training and the results were compared with the control group who were tested twice, at the same time intervals. This was designed to ensure that the students had not just learned how to perform better in fluid intelligence tests because they had done one before. In each test, participants were shown a series of patterns with one area missing and they had to select the correct pattern to fill in this area from a number of choices. The test increased in difficulty as it went on.
What were the results of the study?
The researchers found that all four training groups improved on the training task. Both the training and control groups improved in fluid intelligence between the first and second test, but the training groups improved more than control groups. The improvement increased with increasing duration of training. Improvement was seen with training in people with both high and low pre-training fluid intelligence scores.
What interpretations did the researchers draw from these results?
The researchers concluded that demanding working memory training improves fluid intelligence, even though the training tasks and intelligence tests were completely different. The more training received, the greater the improvements in performance.
What does the NHS Knowledge Service make of this study?
- It was unclear how students were selected for the training or control groups, or for different lengths of training, or what factors training and control groups were matched on. This means that we cannot be sure that the groups were balanced for factors that might affect the results and therefore cannot draw firm conclusions about the benefits of the training.
- The training and intelligence tests conducted here were very specific, and it is not clear whether the same results would be seen if other forms of training or intelligence testing were used. It is also not clear what benefits, if any, the training would have on everyday tasks or normal work performance.
- The volunteers in this study were all young students. The results may not apply to older people or to people of the same age group who were not educated to a similar level.
- Fluid intelligence was tested a short time after completing training; it is not clear how long this effect would last after training finished.
- The study did not report whether tests were analysed blindly, i.e. without the knowledge of which group received training.
Although this study by itself does not prove that brain training improves intelligence, other studies have suggested that keeping the mind active may have various benefits, including a reduced risk of dementia. In general, it would seem sensible to keep the mind as well as the body active. There are many ways to do this, and it does not necessarily require a computerised training program.
Sir Muir Gray adds...
Exercise is good for you.