Lost in the periphery
Visual grasp of scenes goes AWOL around the edges
A new kind of visual illusion confirms that people are not masters of perception. Observers are oblivious to peripheral visions of a woman’s face dissolving into a fountain, a stroller becoming a blob, and windows melding into trees, researchers report online August 14 in Nature Neuroscience.
By studying these visual oversights, scientists hope to understand how the brain culls the flood of visual data that constantly streams into the eyes.
Jeremy Freeman of New York University and Howard Hughes Medical Institute investigator Eero Simoncelli, also of NYU, started the project by developing a mathematical description of how information moves through the visual system in the brain. Their model predicted that the visual system tosses unnecessary information that comes from the periphery. “Your visual system is giving you the information that you need, and it’s throwing away information that you really don’t need,” Simoncelli says.
To see whether this information loss actually happens, the team showed eight people quick flashes — a fifth of a second — of various scenes, scrambled in a way the math model predicted would be undetectable to humans. While fixating on a point in the middle, people couldn’t tell the difference between two very different van Gogh-esque scrambles of a normal scene of a crowd at Washington Square Park in New York City, for example. These scrambles went undetected even when people were allowed to stare at the images for nearly half a second, the team reports.