For more than a century researchers have been trying and failing to link perception and intelligence—for instance, do intelligent people see more detail in a scene? Now scientists at the University of Rochester and at Vanderbilt University have demonstrated that high IQ may be best predicted by combining what we perceive and what we cannot.
In two studies in the journal Current Biology, researchers asked 67 people to take IQ tests. They then viewed milli-second-long video clips in which black-and-white stripes moved left or right. The split-second films challenged viewers: the stripes moved within a circular frame that could differ in size, varying from the width of a thumb to a fist held at arm's length. After each clip, the viewers guessed whether the bars moved toward the left or right.
The investigators discovered that performance on this test was more correlated with IQ than any other sensory-intelligence link ever explored—but the high-IQ participants were not simply scoring better overall. Individuals with high IQ indeed detected movement accurately within the smallest frame—a finding that suggests, perhaps unsurprisingly, that the ability to rapidly process information contributes to intelligence. More intriguing was the fact that subjects who had higher IQ struggled more than other subjects to detect motion in the largest frame.
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The authors suggest that the brain may perceive large objects as background and subsequently may try to ignore their movements. “Suppressing information is a really important thing that the brain does,” explains University of Rochester neuroscientist Duje Tadin. He explains that the findings underscore how intelligence requires that we think fast but focus selectively, ignoring distractions.