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His other unconventional practice is to rely on published data to verify his findings instead of conducting complex experiments, which can be time-consuming, difficult to conduct, and demand more specialized skills than a theorist like himself possesses. “I need the freedom to cut my losses if I’ve worked on an idea for a few months and then need to throw it in the garbage and work on something new,” he says.

Human “superpowers”

Called “prolific” by Scientific American, Changizi has made four major discoveries in the last three years about the visual system’s “superpowers.” His research both has uncovered uncanny abilities and overturned some longstanding erroneous explanations in each of the main subdisciplines of vision: color, object recognition, motion, and binocularity. His first research project, related to why we see in color, was conducted while he was a fellow in the Sloan-Swartz Center for Theoretical Neurobiology at the California Institute of Technology.

“Old-world primates, whose descendents include us, have a different cone receptor in their eyes than the rest of the animal kingdom, and thus they can see very slight color changes,” says Changizi. “For yearsscientists thought that our color vision had adapted to allow us to find the ripest fruits in the forest, but if you look at what these primates eat, the evidence isn’t extremely supportive.”



Fuzzy dot | Short, quick looms toward the center lead to the blurs flowing outward “too fast.”

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Changizi discovered that our ability to see in color is actually designed to allow us to detect subtle changes in the emotional states of our peers.

A fluctuation in oxygenated blood could signal anything from embarrassment—through red cheeks—to going “white with fear.”

“Our ability to see subtle changes in color gives us the ability to read the minds and sense the emotions of those around us,” Changizi says. “We essentially have external sensing equipment for reading emotions, much like the Star Trek empath character [which had the psychic ability to sense the emotions of others].”

Changizi then turned his sights on object recognition by studying why letters across written languages share similar shapes. He discovered that our ancestors likely created their alphabets to mimic shapes that naturally occurred in their environment, exactly the shapes our visual systems have evolved to be great at processing.

“The letter Y, for example, is found on the corners of objects, and the letter T is found when a contour of an object is occluded by another object,” says Changizi. “And similar shapes are found throughout the alphabets of other languages.”

During the two years he’s been a faculty member in the Department of Cognitive Science, which Changizi says he joined because of its diversity of expertise in fields ranging from psychology and logic to artificial intelligence and neuroscience, he’s uncovered two more visual system superpowers.

He argues that our ability to anticipate the future is evident in everything we do, whether it’s catching a football or maneuvering through a crowded room full of people.

It takes our brain nearly one-tenth of a second to translate the light that hits our retina into a visual perception of the world around us. While a neural delay of that magnitude may seem minuscule, imagine trying to catch a ball or wade through a store full of people while always perceiving the very recent (one-tenth of a second prior) past.

While many scientists hypothesized that optical illusions occur because they exploit the limitations of our visual processing, Changizi argues they occur when our brains attempt to perceive the future, and those perceptions don’t match reality.

“We experience countless illusions in our lifetime. The most famous being geometrical illusions—those with converging lines and a vanishing point we often see in Psychology 101 classes or in entertaining optical illusion books,” he says.

The Hering illusion, for example, looks like a bike wheel spoke with two vertical lines drawn on either side of the center vanishing point. Although the lines are straight, they seem to bow out away from the vanishing point. The optical illusion occurs because the human brain is predicting the way the underlying scene would project in the next moment if the individual were moving in the direction of the vanishing point. “Evolution has seen to it that geometric drawings like this elicit our superpower ability to foresee the near future,” says Changizi.

Changizi uncovered the final of the four superpowers in a paper published last summer. He claims the eyes have evolved to face forward in order to allow for “X-ray vision,” or the human ability to see through the clutter in the world.

Most animals—fish, insects, reptiles, birds, rabbits, and horses, for example—exist in non-cluttered environments like fields or plains, and they have eyes located on either side of their head, allowing for panoramic vision.

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