Researchers at The University of Rochester developed a brief visual test that measures the brain's ability to "filter out visual movement".
It is the first test developed that provides a non-verbal and culturally unbiased tool for evaluating intelligence.
As a purely sensory assessment, the test involves watching brief videos of black and white bars moving across a computer screen. The only task is to identify the direction in which the bars are drifting - either to the left or right.
The bars in the videos came in three different sizes, with the smallest only filling the center circle of the screen and the largest filling the whole screen.
The researchers carried out the study, published in the journal Current Biology, using the test as a means of assessing the link between IQ and motion filtering. The results could help researchers understand what makes the brain more efficient.
Duje Tadin, a senior author on the study and an assistant professor of brain and cognitive sciences at the University of Rochester, said:
"Because intelligence is such a broad construct, you can't really track it back to one part of the brain. 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."
In the study, people with high IQs were by far the fastest at identifying the movement of the bars when they were small (filling only the central circle, where human motion perception is known to be optimal).
This is in line with previous studies that have found that intelligent people generally have faster reflexes and make better perceptual judgments. Melnick commented that "being 'quick witted' and 'quick on the draw' generally go hand in hand."
However, when the participants were presented with the largest images, people with the highest IQs were slower at detecting movement.
"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."
The authors explained that being unable to perceive the large moving image shows the brain's ability to suppress background motion.
Duje Tadin commented: "People with higher IQ are quicker at detecting small moving objects, but slower when the objects are larger. This counterintuitive inability to perceive large moving objects is a perceptual marker for the brain's ability to filter out distracting background movement."
The first experiment of this kind only included 12 people and identified a 64 percent correlation between motion suppression and IQ scores. The group of researchers decided to then conduct a second study with a larger cohort of 53 people, where a 71% correlation was found.
Tadin concluded that "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."
What is intelligence? Are IQ tests accurate and relevant?In 2010, researchers from Caltech, USC, the Autonomous University of Madrid and the University of Iowa mapped the brain structures that affect general intelligence. They wrote in Proceedings of the National Academy of Sciences (PNAS) that their findings add new insight to a highly controversial question "What is Intelligence? How can we measure intelligence?"
They examined details from 241 patients who all had brain lesions and had taken IQ tests. The scientists mapped where the lesions were in each paitent's brain, and then correlated their IQ scores to produce a map of the brain regions that drive intelligence.
The researchers wrote "General intelligence, often referred to as Spearman's g-factor, has been a highly contentious concept. But the basic idea underlying it is undisputed: on average, people's scores across many different kinds of tests are correlated. Some people just get generally high scores, whereas others get generally low scores. So it is an obvious next question to ask whether such a general ability might depend on specific brain regions."
They found that general intelligence does not reside in a single structure, but is determined by a network of regions across both sides of the brain.
The authors said that general intelligence depends on a person's brain's ability to pull together several different types of processing, including working memory.
Some experts believe that measuring a child's IQ is an inaccurate way of determining intelligence. Dr. J.P. Das, from the University of Alberta, says that IQ tests label youngsters unfairly.
Dr. Das developed "rules and tools of intelligence" which point to factors other than IQ in measuring how smart a kid is. "A child growing up in the slums or in a household with no literacy or books could be very street-smart, yet not have the school learning required for the traditional measurement of IQ." Das identified four 'rules of intelligence' that go into information processing.
High IQ linked to good rhythmSwedish researchers found that individuals with high IQ test scores were also good at keeping time. They believe that accuracy in timing is important to the brain processes involved in problem solving and reasoning.
The team, from the Karolinska Institutet and Umeå University, showed a correlation between general intelligence and the ability to tap out a simple rhythm. The scientists emphasized that the test participants were involved in a task that had nothing to do with muscial rhythmic sense - they simply measured the capacity for rhythmic accuracy. Participants with the highest IQ test scores were best able to tap out a regular rhythm in the experiment.
Team leader, Fredrik Ullén, said "It's interesting as the task didn't involve any kind of problem solving. Irregularity of timing probably arises at a more fundamental biological level owing to a kind of noise in brain activity."
Written by Joseph Nordqvist