New research indicates there is a strong link between the brain’s ability to ignore useless information and intelligence.
Researchers at the University of Rochester
in New York state say they can predict a person’s intelligence quotient, or IQ, using some simple visual tests.
Test subjects were asked to watch brief video clips of black and white bars moving across a computer screen within three different sized circles. They were asked to identify in which direction the bars drifted.
The exercise measures the brain's unconscious ability to filter out visually distracting background motions. The study, researchers said, shows that individuals whose brains are better at automatically suppressing background motion perform better on standard measures of intelligence such as a written IQ test, which subjects were also given.
According to the study, subjects with higher IQ scores were able to perceive the direction of movement when observing the smallest image. The findings support previous research that people with higher IQs are able to make perceptual judgments more quickly and have faster reflexes.
However, the higher a person's IQ, the slower they were at detecting movement when presented with the larger images.
"From previous research, we expected that all participants would be worse at detecting the movement of large images, but high IQ individuals were much, much worse," says Michael Melnick, a doctoral candidate in brain and cognitive sciences at the University of Rochester.
The key discovery, researchers said, is how closely this natural filtering ability is linked to a person’s IQ score.
Researchers say there was a 64 percent correlation between motion or distraction suppression and IQ scores. Other research exploring the relationship between intelligence and color discrimination, sensitivity to pitch and reaction times only have shown a 20 to 40 percent correlation, scientists said.
"In our first experiment, the effect for motion was so strong," said Duje Tadin, a senior author on the study and an assistant professor of brain and cognitive sciences at the University of Rochester. "I really thought this was a fluke."
The test represents the first non-verbal and culturally unbiased way to assess IQ, researchers said.
"Because intelligence is such a broad construct, you can't really track it back to one part of the brain," said Tadin. "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."
According to the study, the relationship between IQ and motion suppression points to the fundamental cognitive processes that underlie intelligence. The brain’s ability to filter important information from the bombardment of sensory information is an indication of the brain’s efficiency and therefore intelligence.
"Rapid processing is of little utility unless it is restricted to the most relevant information," the authors conclude.
"We know from prior research which parts of the brain are involved in visual suppression of background motion. 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," says Tadin.
The unexpected link between IQ and motion filtering was reported online in the Cell Press journal Current Biology
on May 23.
Here's a sample of the kind of test given: