“Reality” is constructed by your brain. Here’s what that means, and why it matters.

“Most of the time, the story our brains generate matches the real, physical world — but not always. Our brains also unconsciously bend our perception of reality to meet our desires or expectations. And they fill in gaps using our past experiences.

All of this can bias us. Visual illusions present clear and interesting challenges for how we live: How do we know what’s real? And once we know the extent of our brain’s limits, how do we live with more humility — and think with greater care about our perceptions?”

“The stories our brains tell us about reality are extremely compelling, even when they are wrong.”

““The dirty little secret about sensory systems is that they’re slow, they’re lagged, they’re not about what’s happening right now but what’s happening 50 milliseconds ago, or, in the case for vision, hundreds of milliseconds ago,” says Adam Hantman, a neuroscientist at Howard Hughes Medical Institute’s Janelia Research Campus.

If we relied solely on this outdated information, though, we wouldn’t be able to hit baseballs with bats, or swat annoying flies away from our faces. We’d be less coordinated, and possibly get hurt more often.

So the brain predicts the path of motion before it happens. It tells us a story about where the object is heading, and this story becomes our reality. That’s what’s likely happening with Cavanagh’s illusion. It happens all the time.”

“The brain tells us a story about the motion of objects. But that’s not the only story it tells. It also tells us stories about more complicated aspects of our visual world, like color.”

“When we think an object is being bathed in blue light, we can filter out that blue light intuitively. That’s how many of these color illusions work. We use surrounding color cues and assumptions about lighting to guess an object’s true color. Sometimes those guesses are wrong, and sometimes we make different assumptions from others.”

“Night owls, or people who like to go to bed really late and wake up later in the morning, are more likely to see the dress as black and blue. Larks, a.k.a. early risers, are more likely to see it as white and gold. What’s going on?

Wallisch believes the correlation is rooted in the life experience of being either a lark or a night owl. Larks, he hypothesizes, spend more time in daylight than night owls. They’re more familiar with it. So when confronted with an ill-lit image like the dress, they are more likely to assume it is being bathed in bright sunlight, which has a lot of blue in it, Wallisch points out. As a result, their brains filter it out. “If you assume it’s daylight, you will see it as white and gold. Because if you subtract blue, yellow is left,” he says.”

“The owls versus lark data seems quite compelling for explaining a large part of the individual differences,” Schwarzkopf says. But not all of it. “There are still lots of other factors that must have a strong influence here.”

“we have no way of knowing how our experiences guide our perception. “Your brain makes a lot of unconscious inferences, and it doesn’t tell you that it’s an inference,” he explains. “You see whatever you see. Your brain doesn’t tell you, ‘I took into account how much daylight I’ve seen in my life.’””

“Sometimes, especially when the information we’re receiving is unclear, we see what we want to see. In the past, researchers have found that even slight rewards can change the way people perceive objects.”

“In a more complex example, Balcetis has found that when she tells study participants to pay attention to either an officer or a civilian in a video of a police altercation, it can change their perception of what happened (depending on their prior experience with law enforcement and the person in the video with whom they more closely identified). “That instruction changes what their eyes do,” Balcetis told me last summer. “And it leads them to a different understanding of the nature of the altercation.”

You can’t completely remove bias from the brain. “You can’t change the fact that we’ve all grown up in different worlds,” Balcetis said. But you can encourage people to listen to other perspectives and be curious about the veracity of their own.”

“Just as we can look at an image and see things that aren’t really there, we can look out into the world with skewed perceptions of reality. Political scientists and psychologists have long documented how political partisans perceive the facts of current events differently depending on their political beliefs. The illusions and political thinking don’t involve the same brain processes, but they follow the similar overarching way the brain works.”