A recent scientific study is being welcomed as a landmark that shows how fluid intelligence can be improved through training. I interviewed one of the researchers recently (Can Intelligence Be Trained? Martin Buschkuehl shows how), and contributor Dr. Pascale Michelon adds her own take with the great article that follows. Enjoy!

Reference: Jaeggi, S. M., Buschkuehl, M., Jonides, J., & Perrig, W. J. (2008). Improving Fluid Intelligence With Training on Working Memory. Proceedings of the National Academy of Sciences of the United States of America, 105(19), 6829-6833

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What is intelligence?

Intelligence is a concept difficult to define as it seems to cover many different types of abilities.

One definition dissociates between crystallized intelligence or abilities and fluid intelligence. Crystallized intelligence refers to the knowledge acquired throughout life such as vocabulary. Fluid intelligence is the ability that allows us to adapt to new situations or problems.

Age does not affect crystallized and fluid intelligence the same way. In 2004, Schaie and colleagues published the results of the Seattle study. In this study, the researchers collected information on participants over 7 testing cycles (from 1956 to 1998). The results showed that fluid abilities tend to decline earlier than crystallized abilities. In 2004, Lovden and colleagues published the results of the Berlin Aging Study, which included 516 participants assessed 5 times over a period of 13 years. The results show a steady decline in fluid abilities. In contrast, crystallized abilities were quite stable over time and even tended to increase.

Can we train intelligence?

There a lot of drugs that supposedly increase intelligence and makes one smarter. However there is no scientific evidence showing that these drugs have any measurable effects on performance.

In terms of training, several studies have shown that practicing specific tasks will indeed increase performance in these tasks. Problematically, transfer of the training benefits to a different task (not practiced) has been rarely shown.

However, in a very recent 2008 study published in the Proceedings of the National Academy of Sciences, Jaeggi and her colleagues were able to shown that fluid intelligence could be improved by training on working memory. In other words they showed that training young adults using a working memory task induced performance benefits that transferred to fluid intelligence tasks.

Jaeggi and her colleagues trained four groups of young adults using a complex working memory task, called a dual n-back task (Working memory is the ability to hold information for a short while in memory and use that information to solve a problem). In the task participants had to hold in memory both the locations of squares shown on a computer screen and consonants heard through headphones. A response was required whenever one of the presented stimuli matched the one presented n positions back in the sequence. Quite complex as you can see!

Participants (approximately 16 per group) were trained for 25 minutes per day for 8 days, 12 days, 17 days or 19 days. Fluid intelligence was assessed before the training and after the training using standardized tests (consisting in visual analogy problems).

Control groups, who did not receive any training, were also tested for fluid intelligence at the same intervals as the trained groups.

Results showed that the trained groups did better in the fluid intelligence tasks after the training than before the training. Importantly, this gain was greater than the gain seen in the control groups.

Why would the control groups also improve when they did not get any training? They merely had some practice taking the intelligence test given that the test was administered twice (this is why it is crucial to show that the trained groups shows more benefit than the control groups).

This result is one of the rare ones showing that transfer of training gains exists. Here the benefits from being trained on a complex working memory task transferred to a test of fluid intelligence. This is probably possible because working memory and fluid intelligence are related in several ways. First, both require to use attentional and control processes. Second, they both rely on similar neural networks: lateral prefrontal and parietal cortices.

Note that the effect of the training on the intelligence task became significant only after 17 days of training and not before. However, given the small number of participants in each group, one would need more research including more participants to know for sure how many days of training are needed to get a benefit. It would also be interesting to learn how long these effects last…

In conclusion it looks like one can use training to boost one’s fluid intelligence.

Transfer of training effects are really a must, especially in this domain, because new situations come up all the time and you cannot train yourself on all possible situations.

The same argument applies to computerized brain games: playing the same game over and over will increase your performance in that game. But what you really want to see is a transfer of the benefits induced by playing that game to other everyday tasks. More research is needed then!

— This article was written by Pascale Michelon, Ph. D., for SharpBrains.com. Copyright 2008. Dr. Michelon has a Ph.D. in Cognitive Psychology and has worked as a Research Scientist at Washington University in Saint Louis, in the Psychology Department. She conducted several research projects to understand how the brain makes use of visual information and memorizes facts. She is now an Adjunct Faculty at Washington University, and teaches Memory Workshops in numerous retirement communities in the St Louis area.