EAST LANSING, Mich. Prolonged exposure to virtual reality can temporarily rewire the brain's perceptual systems, researchers at Michigan State University have found, but no one knows whether regular, daily doses can have permanent effects and whether they can be remedied.
"Since television was invented in the 1950s, people have accumulated as much as seven years of exposure to TV," said Frank Biocca, who directs the new Media, Interface and Network Design (Mind) Lab. "With the integration of a common VR interface to television, the telephone, personal computers and even the radio, newspapers and books, future generations may accumulate as many as 15 years in virtual environments over their lifespan." One goal of research at Mind Lab is to determine whether the long-term exposure will generate psychophysiological effects that are detrimental to health.
Questions about the possible consequences of using advanced VR equipment has had an impact on the industry. In 1995, virtual reality was poised to become a major industry, with dozens of startups forming and major game and toy makers promising consumer-priced head-mounted displays (HMD) for Christmas. But scaling down the $100,000 lab prototypes caused a nausea reaction called "simulation sickness." There were even reports that extended exposure to inexpensive VR setups could cause LSD-like flashbacks in adults and "lazy eye" in children reports that had a chilling effect on the budding industry. Since then, the only VR products introduced for non-professionals have had stationary displays that do not track head movement and hence do not create the fully immersive experience that marks the difference between VR and simple 3-D rendering.
Air Force call
In 1995, the Air Force, which had developed the HMD, called for more studies on the "long-term psychosocial and psychophysiological effects" of extended exposure to fully immersive VR. The University of Washington's Human Interface Technology (HIT) Laboratory (Seattle) pursued the issue of VR sickness but has become more famous for its subsequent development of non-HMD solutions, such as the retinal display, which directly "writes" images into the eye with a laser.
Biocca said the Mind Lab looks at two types of communications: between human and computer the so-called man/machine interface; and between people.
"Engineers are usually only interested in communication between machines and humans, and psychologists are usually only interested in communications between people," said Biocca. "But we want to look at the effects of virtual environments on both types of communications before they are put into widespread use, so that we can maximize their effectiveness and avoid any pitfalls right from the beginning."
The Mind Lab will pioneer frontiers in communications with ongoing projects in scientific visualization, sensory augmentation and mobile "see-through" VR using wearable computers. One of its first leading-edge investigations will require a student to enter a "see-through" virtual environment on a long-term basis. The gear used includes a monocular display driven by a wearable computer with integral head tracking and wireless transmission to a host that will log the students' experiences. The monocular display will create a "tube" of tactical information around the body of the student that will remain stationary as the student's head is turned. The tactical information will be overlaid on "normal" reality in the fashion of heads-up displays in pilots' cockpits.
A GPS sensor will track the student's movement so that the tube display can change its tactical overlays as appropriate to whatever the student is viewing at any time. A video camera will transmit images every second to the logging host, and a one-minute loop of audio recorded from the environment will be transferred whenever the student pushes a button.
"We call it the recorded-life project because the student will be able to push a button that transfers the current audio loop and sets a cue point that will allow others to later share significant moments in the student's life," said Biocca.
Assistant professor Jannick Rolland at the University of Central Florida's School of Optics cooperated in Biocca's study of the negative psychophysiological effects of long-term exposure to VR.
"My main application of VR is medical, where surgeons are able to augment their view of a patient with diagnostic imagery. Now X-rays, MRIs and other medical images are kept alongside the patient, but we want to merge the images so that they appear right on top of the patient, like a heads-up display in a pilot's cockpit," said Rolland.
The experimental setup used a see-through head-mounted display that augmented reality by overlaying tactical information, such as legends, on top of real-time images. The experiment tried to determine if any intersensory conflicts resulted, so-called sensorimotor adaptation. In particular, the HMD displaced the user's virtual eye position forward by 165 mm and above by 62 mm toward the spatial position of the cameras.
"It turned out that what you see is not where you see it. For instance, say you look at a patient's knee while wearing the HMD. Because of the displacement of the video camera forward and up, you think it is a lot closer than it really is so that when you try to grab it you miss," said Rolland.
After about 10 minutes' exposure, the experimental subjects' brains were able to adapt to the apparent displacement of the objects. However, when the subjects subsequently removed the HMD and viewed the knee without augmentation, their brains overestimated where objects were in their visual field. Fortunately the effect wore off after about 30 minutes. However, that is too long for routine use by doctors during surgery.
"We hope that future studies will show that people can gain enough experience with augmented reality that their brains can adapt to both ways of viewing the world, what we call dual adaptation," said Rolland.
Rolland and Biocca hope to conduct future studies at the Mind Lab that will either demonstrate that people can dual-adapt to viewing the real world and virtual worlds, without lingering aftereffects, or come up with VR technologies to which the brain does not need to adapt in the first place.
"The trade-off is between adaptation and field-of-view," said Rolland. "That is, we can eliminate the need to adapt to VR by providing only a very narrow field-of-view, but for most applications it is desirable to have a wide field of view."