A person can be trained to solve new problems independently of previously acquired knowledge, according to Swiss and American researchers.
The discovery that so-called fluid intelligence (FI), which is closely related to professional and educational success, can be improved contradicts previous findings.
FI is recognised as a complex human ability that allows us to adapt to new problems or situations, in other words our capacity to carry out on-the-spot reasoning. Because of this, it is considered one of the most important factors in learning.
However, most specialists have seen this skill until now as being hardwired in the brain and being little influenced by education or socialisation.
"Until now, the only way of improving your fluid intelligence score was by doing the tests that relate to it," cognitive psychologist Susanne Jäggi told swissinfo. "You figure out how these tests work, so your results get better."
Pharmaceutical solutions to boost this ability have so far shown no proven effect. Computer and video games, contrary to some advertising claims, are not believed to enhance anything beyond some specific tasks and the perception of spatial relationships among objects.
Nor had research shown until now that better performance on skills involving previous training could be transferred to other tasks. "You can evolve strategies for example for words, but you can't use them for numbers," explained Jäggi.
The Swiss researchers took a closer look at so-called working memory – the brain processes which are used for temporarily storing and manipulating information. A number of studies have shown that working memory and fluid intelligence share common traits, such as how much information they can handle.
The Swiss research turns previous findings on their head, showing that FI can be heightened.
Published this week in the journal Proceedings of National Academy of Sciences, the research shows that training a person's working memory boosts their fluid intelligence.
The gains were measured at Bern University by giving the subjects an initial test for fluid intelligence, followed by a series of exercises for improving working memory for up to 19 days. The subjects' FI was then re-tested.
Although the performance of an untrained control group improved slightly, the people who were trained showed a significant performance improvement. The increase depended directly on the amount of time spent training.
How long the improvement actually lasts was not measured and is now part of a follow-up study. But the authors say the initial results have important implications.
"Fluid intelligence is very important in many domains, especially in the academic field," Jäggi said. "In the United States for example people are tested to get into university.
"So if you can actually improve your level, which was considered until now immutable, it could have all sorts of implications for healthy people as well as others with learning disabilities."
The results also show that gains in fluid intelligence are not related to a person's initial ability. It seems people with a lower ability make the biggest improvements, although this still has to be confirmed.
The long-term goal of the research is to develop training methods for people who can benefit from this type of training.
"The students we used for the study can already be considered intelligent, so it is important to develop methods to help those who really need it," Jäggi added.
swissinfo, Scott Capper
Psychologists usually define fluid intelligence (FI) as the ability to find meaning in confusion and solve new problems. This means for example drawing inferences and understanding the relationships of various concepts, independent of acquired knowledge.
This type of intelligence tends to decline during late adulthood. Until now it has been considered innate.
It is usually opposed to crystallised intelligence, which is related to abilities that depend on knowledge and experience.
Together, fluid and crystallised intelligence constitute what is known as general intelligence.
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