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Is it Possible to Increase Intelligence?

When answering this question we must first be careful to define just what it is we mean by intelligence.  See what is intelligence for some of the leading models of intelligence. After all under the most general definitions, this question has an obvious answer; it is clearly possible to improve intelligence. Why did we spend so much time at school if we were not able to improve our ability to learn and solve problems?

In the g factor model of intelligence, these kinds of abilities that it is intuitively obvious can be improved through study, are grouped together under Crystallized Intelligence (Gc). But what about the other key aspect, Fluid Intelligence (Gf), is it also possible for an individual to increase their natural ability to solve novel problems independent on any relevant knowledge or experience they may have.

For most of human history, in fact right up to the end of the twentieth century, it was widely believed throughout scientific and academic communities that it was impossible for someone to increase this kind of intelligence. This was due to the idea that the fundamental characteristics of fluid intelligence were determined by genetic factors.

Increasing evidence from the last two decades has been challenging that point of view, and today there is widespread support for the idea that it is possible to improve Gf.

 At the statistical level, concerning general populations, it appears it is happening naturally. Since the 1980s researchers have repeatedly measured the Flynn effect. Named after James Flynn following his 1987 publication, Massive IQ gains in 14 nations: What IQ tests really measure, the Flynn effect is the apparent gradually increase in a populations IQ, averaging around 3 IQ points per decade.  

There are many different explanations for this effect, from improved nutrition, more test aware children, to more stimulating environments. None of these explanation can conclusively demonstrate it alone is responsible, and it is entirely possible a more complex interaction of these and more factors combine to give improved IQ score. What is clear, is the effect is real; the increase is consistently seen in populations from all across the globe.  

For the time being let us leave the gradual statistical march of IQ scores, and turn our attention to the individual, as this may have a far greater significance on our understanding of intelligence. Is it possible for a person to make a noticeable improvement in their own intelligence?

Developments in neuroscience are repeatedly demonstrating the phenomenal plasticity of the human brain. Studies such as; Neuroplasticity: Changes in grey matter induced by training by Draganski et al, have shown that mentally stimulating training induces selective structural changes within the brain. These changes in turn improve the mental processing associated with a particular skills or ability.

Structural Changes in the Brain

Are these structural changes in the brain useful for improving Gf?

The key in the search for a training regimen that would allow an individual to improve their intelligence is that any gains they make must be transferrable. A wide variety of ‘Brain Training’ games and activities have been put examined, and unfortunately the results have not been promising. Owen et al, summarised their finding in Putting brain training to the test, as “Although improvements were observed in every one of the cognitive tasks that were trained, no evidence was found for transfer effects to untrained tasks, even when those tasks were cognitively closely related”.

Although this finding is repeatedly reinforced for the vast majority of brain training exercises, it appears not all brain training games are created equal. In 2008, Suzanne Jaeggi, Martin Buschkuehl,
John Jonides, and Walter Perrig. published their study Improving fluid intelligence with training on working memory. They showed, using a particular cognitive training exercise known as Dual N-Back, that participants could through developing their working memory, achieve a lasting and transferrable increase in their fluid intelligence.

The findings of Jaeggi’s study have since been replicated. The success of these studies suggests a new approach; perhaps certain mental attributes like working memory formed a foundation to Gf. By improving these, individuals would also experience a knock on improvement in Gf.

More exercises that improve working memory have now been discovered, and further candidates for foundational attributes that underlie fluid intelligence have also been identified. Although the field is still in its infancy, there can now be little doubt, it is possible for people to increase their intelligence.