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Vision Scientist Studies Color Contrast, Illusions

Arthur Shapiro

Professor Arthur Shapiro. Photo credit: Sonja Patterson

Your eyes may be playing tricks on you. Without your even knowing it.

“The whole world is an illusion,” says Arthur Shapiro, a vision science researcher and psychology professor

“It’s easy to believe that when you look out into the world, you’re seeing what’s really there and not just a representation of what’s really there. The distinction between our perceptions and reality is an important one, and people should understand it,” he adds, “as much as they can.”

He recently received a National Institutes of Health grant for his project “Separating the Visual Response to Color from the Visual Response to Color Contrast” and research is already underway at American University, where students assisting him include PhD candidate Erica Dickson and undergraduates Oliver Flynn, Alex Rose-Hening, Sean Burn, and Maddi Winkler. “I’ve assembled a great team of students, and we’re having a good time going after complex questions,” he says.

“It’s fun—both scientifically and because my students are here. This research crosses over between science and art, and I think we’re doing some good in the world.”

Shapiro has created many new visual illusions that have won international awards. He’s also currently coediting a book, the Oxford Compendium of Visual Illusions, with Professor Dejan Todorovic of the University of Belgrade, Serbia. Why optical illusions? Because, he says, “Illusions can inform us of how our brain constructs our reality.”

Shapiro was a mathematics and computer science major as an undergrad at the University of California, San Diego, but after attending a cognitive science meeting on a whim, everything changed. He describes himself as “a mathematician who had an attack of philosophy.”

“Like many people who do that,” he says, “I ended up in psychology.”

Shapiro did his PhD dissertation at Columbia University, working on “how we adapt to color and what happens in the brain when colors change over time, which is important for understanding how we move from one environment to the next.” He then conducted research on low-light-level vision during his NIH-funded post-doc at the University of Chicago.

As an assistant professor at Bucknell University, Shapiro took a junior sabbatical leave to conduct research at the University of Cambridge, when he focused again on an obstacle he encountered while working on his dissertation at Columbia: “Studies had shown that the brain reacts very slowly to changes in color in comparison to changes in brightness, but during my sabbatical, I found situations where the brain was adapting quickly to changes in color.”

His key insight came in 2002: he figured out a way to “make experimental stimuli that could separate color and color contrast.”

He spent the next five years building on this idea, conducting experiments and presenting the results in journal articles and conference presentations. The initial visual stimulus that he created led to many visual illusions that separate the visual perception of color from the perception of color contrast.

Shapiro says, “The visual system cares as much about the difference between two objects as it does about the object itself.” He adds, “We just don’t usually talk about color contrast because we don’t have a noun for ‘the-difference-between-the-object-and-its-background-color.” 

Although scientists have been working on color vision seriously for centuries, the understanding of what's happening in the brain has changed drastically in the last two decades, Shapiro says. "My research is an attempt to build an understanding of color vision that merges previous models with new neuroscience research."

His 2008 research led to the development of a mathematical model, in which he set forth a new way of thinking about color vision in terms of separate color and color contrast responses.

Shapiro’s research is relevant at many different levels, from the artistic level to, more importantly, the health level. Variations from the norms for color vision often indicate vision problems. “The techniques I describe in my recently funded grant proposal are new and can be applied to the study of congenital stationary night blindness and to visual decline that occurs as the result of normal aging.”

One of Shapiro’s goals is to construct vision tests for faster diagnoses of different types of eye disease. “It’s important to figure out which part of a visual deficit is due to how the eye operates and could therefore be corrected with glasses, and which part is due to disease and therefore cannot be corrected with glasses.”

When explaining that what we perceive differs from reality, Shapiro says, “In order for us to understand our world, energy has to be transformed from something external—light or sound or chemicals for taste and smell—and the brain has to translate those signals to something which it understands, which is the actions of neurons. If what you perceive has to be reduced to the actions of neurons, then you don’t have direct access to the things that are there, to the objects themselves.”

Your brain constructs your reality—your eyes capture it.