How can you do illusions

Stephen L. Follow Stephen L. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. Get smart. Sign up for our email newsletter. You remember The Dress , yes? In , a bad cellphone photo of a dress in a UK store divided people across the internet. Some see this dress as blue and black; others see it as white and gold.

Is it in bright daylight? Or under an indoor light bulb? By unconsciously filtering out the color of light we think is falling on an object, we come to a judgment about its color.

Wallisch believes people who see this image differently are using different filtering schemes. Most interestingly, he suggests that life experience leads you to see the dress one way or the other. His study of 13, people in an online survey found a correlation that at first seems odd. The time you naturally like to go to sleep and wake up — called a chronotype — was correlated with dress perception.

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. 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. 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. Night owls, he thinks, are more likely to assume the dress is under artificial lighting, and filtering that out makes the dress appear black and blue. But not all of it. But we have no way of knowing how our experiences guide our perception. Wallisch says the disagreements around The Dress, as well as other viral illusions like Yanny and Laurel , arise because our brains are filling in the uncertainties of these stimuli with different prior experiences.

We bring our life histories to these small perceptions. In this illusion, the Pac-Man-like shapes give the impression of a triangle in our minds. We only need the suggestion of one — implied via the corners — to fill in the rest of the picture with our minds. It may be that a lifetime of looking at triangles is what makes the rest of us see one so plainly in this image. He had to build them from scratch. What is the same is that I am still guessing.

The horizontal lines are actually parallel, and not at all slanted. Look at the distance between them at the start and end of each row if you don't believe it. Wonderful version of the cafe wall illusion, by Victoria Skye. Some of these examples may seem frivolous. Why does it matter that one person sees a dress as black and blue and another sees it as white and gold? It matters because scientists believe the same basic processes underlie many of our more complicated perceptions and thoughts.

In the past, researchers have found that even slight rewards can change the way people perceive objects. Take this classic image used in psychological studies. What do you see? In one experiment, the participants played a game wherein they had to keep track of animals they saw on screen. In the end, a high score meant getting a candy treat desirable! The very last thing the participants saw was the above image. 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.

But you can encourage people to listen to other perspectives and be curious about the veracity of their own. The neuroscientists I spoke to said the big principles that underlie how our brains process what we see also underlie most of our thinking. The ambiguity is going to be resolved one way or another, and sometimes in a way that does not match reality. Political scientists and psychologists have long documented how political partisans perceive the facts of current events differently depending on their political beliefs.

In a way, you can think of bias as a social illusion. Studies find that many people perceive black men to be bigger and, therefore, potentially more threatening than they actually are , or generally associate darker skin tones and certain facial features with criminality. Cops can confuse people removing wallets from their pockets with people reaching for guns, often with tragic consequences.

Our brains work hard to bend reality to meet our prior experiences, our emotions, and our discomfort with uncertainty. This happens with vision. But it also happens with more complicated processes, like thinking about politics, the pandemic , or the reality of climate change. Wallisch has come up with a name for phenomena like The Dress that generate divergent perceptions based on our personal characteristics.

And because we have different priors, that leads to disagreement about the image or event in question.

Wallisch sees it everywhere in society. I recently tweeted some frustration over how mass protests against police brutality might be perceived if it seems as though they led to increased Covid cases. Want to see an example in action? Take a look at the image above. Think of it as a ghost image overlapping a new image.

When similar patterns are repeated and merged together, it changes your visual perception of the object. Today, neuroscience and optical illusions are tightly woven together because researchers view them as more than entertaining brain games. They use optical illusions to study the human brain, namely how it interprets the information our eyes send to it.

Your eyes take in an enormous amount of information very quickly. In fact, it only takes 13 milliseconds for the human eye to process an image. Sounds exhausting, right?