IQ tests cannot measure true intelligence: study

The landmark study which included more than 100,000 participants asked respondents to complete 12 cognitive tests tapping memory, reasoning, attention and planning abilities, as well as a survey about their background and lifestyle habits.

The study by researchers from Western University in Canada showed that when a wide range of cognitive abilities are explored, the observed variations in performance can only be explained with at least three distinct components: short-term memory, reasoning and a verbal component.

No one component, or IQ, explained everything. Furthermore, the scientists used a brain scanning technique known as functional magnetic resonance imaging (fMRI), to show that these differences in cognitive ability map onto distinct circuits in the brain.

With so many respondents, the results also provided a wealth of new information about how factors such as age, gender and the tendency to play computer games influence our brain function.

"Regular brain training didn't help people's cognitive performance at all yet ageing had a profound negative effect on both memory and reasoning abilities," said Adrian M Owen, senior investigator on the project.

"Intriguingly, people who regularly played computer games did perform significantly better in terms of both reasoning and short-term memory. And smokers performed poorly on the short-term memory and the verbal factors, while people who frequently suffer from anxiety performed badly on the short-term memory factor in particular," researcher Adam Hampshire said in a statement.

"To ensure the results aren't biased, we can't say much about the agenda other than that there are many more fascinating questions about variations in cognitive ability that we want to answer," explained Hampshire.