Optical illusions may predict IQ

Those optical illusions that have confounded generations of curious minds may actually be a strong indicator of intelligence, a new study has found. According to research published in Current Biology, people with a higher IQ are able to focus on the details and disregard less relevant information with greater ease than their less intelligent counterparts.

This new revelation means that mental focus may be the key to higher scores on intelligence tests.

“Our brains operate on overwhelming amounts of information, and thus their efficiency is fundamentally constrained by an ability to suppress irrelevant information,” write the authors in the study.

The authors came to this conclusion after having a set of participants take an IQ test and watch a video, which included movement in both the foreground and background of the frame. In the foreground, there was motion in small circles. In the background, the video contained larger black-and-white stripes.

Individuals with a high IQ were able to process changes in details and movement in the circles, but struggled as the stimulus size increased and moved to the background. Individuals with a lower IQ were better at perceiving changes with the black-and-white stripes but less accurate with the smaller actions occurring in the foreground.

“We show that individual variability in a simple visual discrimination task that reflects both processing speed and perceptual suppression strongly correlates with IQ,” write the authors. “High-IQ individuals, although quick at perceiving small moving objects, exhibit disproportionately large impairments in perceiving motion as stimulus size increases.”

Fundamentally, this means that IQ scores can be predicted by individual differences in sensory discriminations. The results indicate that more intelligent people are able to suppress sensory information to focus on details. This means that higher intelligence does not necessarily mean that a person’s brain has increased processing power. Rather, the study suggests that those with higher intelligence think more efficiently.

The authors say that this correlation is logical because suppressive processes are a key constraint of both intelligence and perception.

“The ability to suppress irrelevant and rapidly process relevant information fundamentally constrains both sensory discriminations and intelligence,” write the authors. “These findings link intelligence with low-level sensory suppression of large moving patterns—background-like stimuli that are ecologically less relevant.”