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Humans and other large mammals—primates and large carnivores like tigers, for example—exist in cluttered environments like forests or jungles, and their eyes have evolved to face forward, with a larger overlapping binocular field. Many have argued this was so primates could see in three dimensions as they jumped from limb to limb, but Changizi found these animals have been selected for maximizing the ability to see in leafy environments like forests.

“Our binocular region is a kind of ‘spotlight’ shining through the clutter, allowing us to visually sweep out a cluttered region to recognize the objects beyond it,” he says. “As long as the separation between our eyes is wider than the width of the objects causing clutter—as is the case with our fingers, or would be the case with the leaves in the forest—then we can tend to see through it.” 

RE Vision

Hering | The Hering illusion is exemplified by the perceived curvature of the straight lines near the vanishing point in the center of the drawing.
Changizi discusses the four superpowers—emotion sensing, spirit-reading, future seeing, and X-ray vision—in his new book, The Vision Revolution. Changizi wrote the book for both a general audience and the scientific community.

“I really admire the work of [Harvard professor and author] Steven Pinker, whose books focus on scientific topics in a way that is accessible to all readers, not just scientists,” says Changizi. “In that same vein, I was cognizant to try to write something that anyone could read, understand, and find interesting and inspiring—without compromising the scientific explanations for why our visual systems have evolved to behave the way they do. Laymen like a trade science book most of all when they feel that the book is part of the scientific conversation, not something written just for laymen.”

The book, which already has garnered mentions in The New York Times and Scientific American, is not the end of the literary road for Changizi, who has turned his sights to his next book. “I’m in the process of working on a proposal for a second trade book based on new research into how language mimicked nature, like how the sounds of speech sound like naturally occurring events,” he says.

Changizi also has received accolades for his classroom teaching. The 2008 recipient of Rensselaer’s Class of 1951 Teaching Development Grant awarded to faculty members for their outstanding accomplishments in education, Changizi has introduced innovative new coursework for undergraduate students. Last spring, for example, he taught The Cognitive Science of Art, an interdisciplinary course he developed for cognitive science and arts students that focused on uncovering various cognitive principles ingrained in artwork.

Orbison | With the Orbison geometric illusion, the squares closer to the center of the image seem larger than those on the outside of the drawing.
He also taught a daylong course to a digital circuits class focused on a new technique he created to harness the computing power of the visual system to carry out digital circuit and logic computations.

By visually representing a computer program in such a way that, when viewed by an individual, that person’s visual system naturally carries out the computation and generates a perception, Changizi showed his students that it might be possible to one day glance at a complex visual stimulus (the software program) and have the visual system (the hardware) automatically generate a perception of the output of the computation. 

He has begun to apply his approach by developing visual representations of digital circuits. A large and important class of computations used in calculators, computers, phones, and most of today’s electronic products, digital circuits are constructed from assemblies of logic gates and have an output value of zero or one. 

“A digital circuit needs wire in order to transmit signals to different parts of the circuit. The ‘wire’ in a visual representation of a digital circuit is part of the drawing itself, which can be perceived only in two ways,” says Changizi, who created visual stimuli to elicit perceptions of an object tilted toward (an output of one) or away (an output of zero) from the viewer. “An input to a digital circuit is a zero or one. Similarly, an input to a visual version of the circuit is an unambiguous cue to the tilt at that part of the circuit.”

Changizi says his students “loved the seminar,” and he hopes to obtain financial support to create a semester-long course in visual circuits in order to measure the learning curve of this new way to teach digital circuits, compared with the traditional method.

“People are notoriously poor logical reasoners—someday visual circuits may enable logic-poor individuals to ‘see their way’ through complex logical formulae,” he says.

And while he’s succeeded at changing the way his students (literally) see digital circuits, and his scientific peers see the groundbreaking evolutionary reasoning behind the mechanisms of the visual system, Changizi is still hard at work. There are more questions to ask, more notebooks to fill, more answers to find.

“There is always more to discover about why we are the way we are,” he says. “The tricky part is putting your finger on the right question—that crazy-sounding question—that allows you to uncover an important answer.”

* “Uncovering the human superpowers”  Page 1 | 2 | 3 | 4     Previous   *
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Rensselaer (ISSN 0898-1442) is published in Spring, Summer, Fall, and Winter by the Office of Strategic Communications and External Relations, Rensselaer Polytechnic Institute, Troy, NY 12180-3590. Opinions expressed in these pages do not necessarily reflect the views of the editors or the policies of the Institute. ©2009 Rensselaer Polytechnic Institute.