Whatever Happened to Virtual Reality?

Since the 1980s there has been a dawning awareness among researchers that human factors are crucial to virtual reality. Age, gender, health and fitness, peripheral vision, posture, the sensitivity of the vestibular system: all of these things come into play. Even self-image matters. One study showed that people wearing virtual reality helmets like to glance down and see their own virtual body. It helps "ground them" in the simulation. And the body should be correct: arms, legs, torso; male for men; female for women.

For every virtual environment, there is a human-computer interface, and if the interface doesn't match the person … game over.

To address these human factors, Ellis's group performs fundamental research on human senses and perception. One central concern is how people cope with "latencies," or delays, in the virtual reality system. When you swing your head, does the virtual view follow immediately, or is there a split-second lag? If your eyes and your inner ear (where vestibular organs sense orientation) send conflicting reports to the brain, you might need a motion-sickness bag.

more Organs in the inner ear (the vestibular system) affect human balance. Vestibular adaptation is a key human factor in Virtual Reality interface design.

"The question is how much delay can you tolerate?" Ellis says. For movement within the virtual environment to feel natural, most people need the delay to be less than 15 milliseconds (thousandths of a second), according to his group's research.

Bernard Adelstein, Durand Begault, and Elizabeth Wenzel, colleagues of Ellis who work in the Advanced Displays Laboratory at Ames, have discovered that, because sounds in a virtual environment can be generated much faster than touch feedback from a virtual reality glove, sound can help compensate for the delay in touch. For example, when grabbing a virtual object, the immediate "click" sound of contact enhances the user's tactile perception of realism.

The years of research are finally beginning to pay off, Ellis says. "The fully immersive, head-mounted system is getting to be high enough fidelity for practical use. We'll probably have the AERCam virtual reality experiment running by August."

The Matrix will take a little longer.