We, as humans, tend to ascribe a lot of weight to numbers. Perhaps that’s an easy way for us to make sense of the world. Consider, though, IQ scores. Can you accurately judge a person’s intelligence by an IQ test?

Not according to a recent study from Western University scientists who found that measuring a person’s IQ by a single, standardized test is misleading.

The scientists–who used an online study open to everyone worldwide and included more than 100,000 participants–asked people to complete 12 cognitive tests on memory, reason, attention and planning abilities. Participants were also asked about their backgrounds and lifestyle habits.

“The uptake was astonishing,” said Adrian M. Owen, the Canada Excellence Research Chair in Cognitive Neuroscience and Imaging and senior investigator on the project at Western’s Brain and Mind Institute in London, Canada. “We expected a few hundred responses, but thousands and thousands of people took part, including people of all ages, cultures and creeds from every corner of the world.”

Result’s from the study 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 aging had a profound negative effect on both memory and reasoning abilities,” Owen said.

“Intriguingly, people who regularly played computer games did perform significantly better in terms of both reasoning and short-term memory,” said Adam Hampshire from Western’s Brain and Mind Institute. “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.”

If you’re interested in helping with this research, the scientists have launched a new version of the tests at http://www.cambridgebrainsciences.com/theIQchallenge.

(Story materials and image from Western University.)