The world around us seems full of color. But you don’t see as much of that vibrant world as you think. In a new study, when scientists drained the color out of 70 percent of a virtual environment, the vast majority of viewers never noticed. Even when only five percent of the view had color, almost one in three viewers never had a clue.
“We think we’re aware of more than we are,” says Michael Cohen. He’s a neuroscientist — someone who studies the brain — at Amherst College in Massachusetts. “We as humans are bad at knowing our limits.”
Cohen and his colleagues wanted to get a better picture of how much we really see in the world around us. They put 160 college students in virtual reality. This is a 3-D simulation of the real world. To immerse themselves in this environment, people wear special goggles. Those goggles let them wander and explore new places — even though they aren’t physically in those places.
The scientists tried to make the scenes as realistic as possible. “The majority we pulled off YouTube,” Cohen says. “We had some [where] the camera was in the middle of a penguin enclosure. Or the in the middle of a symphony rehearsal. There was one with those Komodo dragons. People [in the study] really enjoyed it.”
Once the students were in the virtual world, they were told to walk around. While they did, Cohen and his team tracked where the students’ eyes moved as they explored.
Then, the scientists began to drain color out of the scene. But they only drained it out of someone’s peripheral vision. That’s areas at the outer edge of what you can see. You have peripheral vision to the bottom, top and both sides of anywhere you look. Because the scientists were tracking where people’s eyes were moving, they could ensure that where people were looking continued to have color. They let only the edges fade to black and white.
A world without (most) color
Most people never noticed what the scientists were doing. Cohen and his colleagues took the color out of roughly three-quarters of the visual field. Yet only 17 out of every 100 participants ever noticed.
Slowly, the researchers removed more and more color from a scene. Eventually, only a tiny spot of color was left bouncing within a participant’s gaze around the virtual world. But even when the color region was dropped to just five percent, 30 in every 100 students didn’t realize that almost all of the world around them was in black and white.
Some of this inattention might be explained by how the people interacted with that virtual world. If they were just looking around, they weren’t paying attention to their peripheral vision.
Cohen and his colleagues tested this in a second experiment. Here, they asked the students to focus. They told the volunteers that the color in their peripheral vision would go away and asked them announce when they noticed this. Even when told to look for a world gone gray, the students didn’t notice until about two-thirds of the color was gone.
“We weren’t surprised that we got an effect, but we were surprised that we got such a big effect,” Cohen says.
He and his colleagues published their findings June 8 in the Proceedings of the National Academy of Sciences.
The study demonstrates what scientists call attentional bias. This is when people ignore things on which they’re not focused. This isn’t always a bad thing. There’s so much in the world, the brain needs to focus. To do that, it must give some things less importance, at least for a while.
Cohen also was not surprised that the color change fooled so many. Our eyes contain cones, which are the cells that sense color, and rods, which sense motion. Cones tend to be concentrated in the fovea. That’s the part of the eye we use to focus on what we’re looking at. The rest of the eye has more rod cells. This means that the eye isn’t very good at seeing color in your peripheral vision. “You can see some color in the periphery, but it’s way worse compared to something like seeing motion,” he explains.
Andrew Haun is a vision scientist at the University of Wisconsin in Madison. “Displays in virtual reality, that’s pretty new. I don’t think I’ve seen another study doing this yet,” he says. However, he notes, this new study is similar to the gorilla experiment. In that, a participant views a video and is asked to count how many times a group of people pass a basketball. As the viewer counts, someone dressed as a gorilla walks right through the group passing the ball in the video. Most viewers never notice the gorilla — even when it stops to do a funny dance.
“You have to realize your visual experience is all in your head,” Haun says. It might seem like you see a large amount of the world at a time. But you only truly see what you’re focused on. “If you think you know everything that’s there,” Haun says, “that’s an illusion.”