Those of us involved with computer graphics understand the power of visualizations to convey meaning. Because we’re among the most visually oriented people on the planet, we can relate to the notion that humans are visual creatures—that more of the human brain (nearly half) is devoted to processing visual information than to any other task, and that once engaged, our visual processing centers open high-bandwith connections to other brain functions and stimulate higher-order thinking. And we can readily cite examples of how scientific visualizations help us see the unseen and understand the world in new ways.
But while the benefits are real, and the pursuit of creating ever more potent graphics is worthwhile, it's important to remember that images alone can't do the whole job of conveying meaning. This was one theme to emerge during a four-day conference called "Image and Meaning: Envisioning and Communicating Science and Technology" held recently at MIT. The group of presenters, which included some of the most acclaimed scientists, engineers, and communicators of our time, extolled the virtues of visualizations, but also reminded us of their limitations.
Sir Roger Penrose-a professor of mathematics at the University of Oxford who was honored in the 1960s for his theories about black holes and (with Stephen Hawking) about the big bang-relies heavily on visualization to gain insight and understanding. "Images are absolutely vital for exploratory mathematical thinking," he says. "In my notebooks, I have far more pictures than calculations, because when a problem is reduced to calculation, it's almost solved. Whereas it's enormously difficult to come to grips with conceptual ideas without having some kind of images. They're also extremely valuable in getting ideas across to non-mathematicians."
Edward O. Wilson, a Harvard evolutionary biologist who was awarded the National Medal of Science for his research as well as two Pulitzer Prizes for his ability to communicate his findings, also depends on images. In fact, in his forthcoming 800-page book, which chronicles his decade-long study of ants, he includes 5000 illustrations of 625 ant species, 325 of which are new to science. "In biology, we are focused on and driven by images," he says. "The illustrations allow me to enter the habitat and get visual feedback about the traits and behaviors of the species,... to learn detail deep in consciousness and look for patterns. Many discoveries in biology are made this way, by learning to live with the organism."
But several noted engineers and scientists asserted that in their fields even the most sophisticated computer-generated visualizations and animations cannot, by themselves, play more than a supporting role. For example, William Mitch ell, dean of MIT's school of architecture and planning, claims that while image production is central to architectural engineering, different levels of abstraction are required for various stages of the de sign process, and at some point the architect will need a physical model to ex amine and handle. "No architectural designer would do without this type of tactility," he says.
Likewise, Arthur Olson, a professor at the Scripps Research Institute, creates state-of-the-art 3D computer models of molecules, including HIV protease molecules, to visualize on screen what is impossible to see in any other way. But he will then create physically accurate plastic and rubber models based on the digital representations, which he can then hold and manipulate to gain a greater understanding of molecular structures, properties, and forces.
Finally, Susan Sontag, one of the major literary and cultural voices in America, offered perhaps the harshest critique about the inability of images to confer meaning. In fact, she wonders what images, namely familiar or iconic images, really stand for other than a kind of shorthand or visual sound bite. "I'm not sure how much we really understand from these images beyond our preexisting assumptions and arguments. My feeling is that we remember through images, but we understand through words. It's not so much that the images are speaking to us; it's that we're speaking to them. We use images as platforms for associations, and we have to understand that they are seen in a context."
Of course, much context in science visualizations comes from numbers and formulas as well as words. Alan Lightman, physicist, novelist, and chair of the humanities department at MIT, pointed out that "in the history of modern science, a central measure of progress has been the degree to which knowledge can be ex pressed in numbers, equations, and concepts. A ball takes 1.3 seconds to fall a distance of 30 feet. The electrical force between electrons varies with the square of the distance between them. The energy of a closed system is always the same. To represent a concept or a result in this form has usually been considered the most precise form of understanding nature."
But Lightman adds that our minds and imaginations react differently to numbers and equations than they do to pictures and images and other forms of input. "Somehow we assign meaning to the billions of sensory inputs constantly flooding our brain, somehow we think, somehow we create new ideas," he says. "Scientists are dedicated to the study of physical phenomena, atoms, molecules, DNA, computers, galaxies. But of all the wonderful mysteries of nature, nothing is more mysterious or profound than the human mind."
We may never solve that mystery. In fact, Czech mathematician Kurt Goedel's "Incompleteness Theorem," loosely interpreted, says that any logical system-which by implication includes the human brain-is incomplete and therefore incapable of fully understanding itself. Nevertheless, perhaps the biggest step we can take toward reaching a new level of understanding about ourselves and the world we live in is to devise tools that can help us process as many types of input as possible-including images, tactile feedback, words, numbers, and other sensory data-and thus engage more of our logical and creative processes in a coordinated manner. Indeed, for developers of computer graphics visualization and simulation tools, there may be no worthier challenge or higher goal.