Scientists did not invent the vast majority of visual illusions. Rather they are the products of artists who have used their insights into the workings of the human eyes and brain to create illusions in their artwork. Long before visual science existed as a formal discipline, artists had devised techniques to “trick” the brain into thinking that a flat canvas was three-dimensional or that a series of brushstrokes in a still life was in fact a bowl of luscious fruit. Thus, the visual arts have sometimes preceded the visual sciences in the discovery of fundamental vision principles through the application of methodical—though perhaps more intuitive—research techniques. In this sense, art, illusions and visual science have always been implicitly linked.
It was only with the birth of the op art (for “optical art”) movement that visual illusions became a recognized art form. The movement arose simultaneously in Europe and the U.S. in the 1960s, and in 1964 Time magazine coined the term “op art.” Op art works are abstract, and many consist only of black-and-white lines and patterns. Others use the interaction of contrasting colors to create a sense of depth or movement.
This style became hugely popular after the Museum of Modern Art in New York City held an exhibition in 1965 called “The Responsive Eye.” In it, op artists explored many aspects of visual perception, such as the relations among geometric shapes, variations on “impossible” figures that could not occur in reality, and illusions involving brightness, color and shape perception. But “kinetic,” or motion, illusions drew particular interest. In these eye tricks, stationary patterns give rise to the powerful but subjective perception of (illusory) motion.
This article includes several works of art in which objects that are perfectly still appear to move. Moreover, they demonstrate that research in the visual arts can result in important findings about the visual system. Victor Vasarely, the Hungarian-French founder of the op art movement, once said, “In basic research, intellectual rigor and sentimental freedom necessarily alternate.”
Op artists have created some of the illusions featured here; vision scientists honoring the op art tradition have created others. But all of them make it obvious that in op art, the link between art and illusory perception is an artistic style in and of itself.