An interesting article on Kurzweilai regarding a large research study conducted by a Canadian Western University research team which concluded that the concept of a general intelligence or 'IQ' is highly misleading.
The online study, which was open to the general public, asked respondents to complete 12 cognitive test on memory, reasoning, attention and planning abilities, as well as a survey about their background and lifestyle habits. The results showed that variations in performance on the tests could only be explained with at least three distinct components: short-term memory, reasoning and verbal ability.
According to senior investigator Adrian M. Owen "Regular brain training didn't help people's cognitive performance at all yet aging had a profound negative effect on both memory and reasoning abilities."
Researcher Adam Hampshire stated "Intriguingly, people who regularly played computer games did perform significantly better in terms of both reasoning and short-term memory".
I find it very interesting that "brain training" doesn't seem to help cognitive performance yet those who regularly play video games performed better. Of course correlation doesn't necessarily mean causation. Perhaps individuals that possess higher cognitive abilities find video games more appealing than those with average and (or) below average abilities. On the other hand, if there is something about playing video games which enables one to enhance their cognitive functions then this would indicate that regular "brain training" could actually be beneficial but that it is currently done wrong.