Simple Vision Test Predicts IQ: Ignoring Distractions Reveals Intelligence (Video)

How do you predict IQ? Apparently you don't need a lengthy written test. A new study reveals that a brief visual task can actually predict a person's intelligence.

In order to examine how IQ might be measured in a simplistic test, researchers recruited volunteers to watch brief video clips of black and white bars moving across a computer screen. Their sole task was to identify which direction the bars drifted: to the right or to the left. The bars themselves were presented in three sizes, with the smallest version restricted to the central circle where human motion perception is known to be optimal, an area roughly the width of the thumb when the hand is extended. The participants also took a standard intelligence test.

"Because intelligence is such a broad construct, you can't really track it to one part of the brain," said Duje Tadin, a senior author of the study, in a news release. "But since this task is so simple and so closely linked to IQ, it may give us clues about what makes a brain more efficient and, consequently, more intelligent."

So what did the researchers find? People with higher IQ scores were faster at catching the movement of the bars when observing the smallest image. Yet the tables were turned when presented with larger images; those with a higher IQ were slower at detecting movement.

This finding, though, wasn't completely surprising. This counter-intuitive inability to perceive large moving images is probably a perceptual marker for the brain's ability to suppress background motion. This means that people with a higher IQ can concentrate on a single point better--a skill that's more useful in general. When you drive in a car or walk down a hall, the background is constantly in motion while the smaller foreground is more important.

But how closely can this visual test actually measure IQ? The first experiment found a 64 percent correlation between motion suppression and IQ scores--that's a much stronger relationship than other sensory measures to date. After rerunning the experiment with an extended IQ test, the researchers found a 71 percent correlation.

"We know from prior research which parts of the brain are involved in visual suppression of background motion," said Tadin. "This new link to intelligence provides a good target for looking at what is different about the neural processing, what's different about the neurochemistry, what's different about the neurotransmitters of people with different IQs."

The findings could help remove some of the limitations associated with standard IQ tests. Since the visual test is simple and non-verbal, it can help researchers better understand neural processing individuals with intellectual disabilities.

The findings are published in the journal Current Biology.

Want to test yourself? Check out the video below, courtesy of YouTube and the University of Rochester.