Lifelike, computer-generated special effects in film. Multiuser games on the Internet. High-tech videoconferencing systems. Simulation rides such as Universal Studios' Back to the Future attraction.

As the lines between virtual and actual worlds blur, technology is altering our perceptions of what is real.

Nearly 70 researchers, educators, psychologists and artists pondered what "being there" really means in the 21st century during an international conference on electronic media and virtual reality at Temple University last week.

"Presence 2001" was the fourth annual forum for a growing field that crosses several academic disciplines. The three-day event, hosted by Temple's School of Communication and Theater, was the first of the conferences held in the United States.

Keynote speaker Carrie J. Heeter, a professor at Michigan State University, might be considered Exhibit A for the use of virtual reality in the classroom.

Heeter, a full-time professor of digital media arts, teaches her classes of students in Michigan, runs design labs on campus, participates in faculty meetings, and serves as an adviser to the MSU Virtual University - all from her California basement, which is outfitted with five computers.

She moved from East Lansing, Mich., to San Francisco four years ago.

"One of the things about being one virtual person trying to interact with a roomful of physical people is that you really need to work at it," she said.

Heeter, who hates videoconferencing, participates in faculty meetings by speaker phone. To remind her colleagues in Michigan that she is "there," she has taped a photograph of herself to a coat rack and placed it at the conference table.

She told the Temple conference about a recent experiment in Michigan in which large-screen picture phones successfully created a sense of "being there" for homebound senior citizens. The screens installed in their living rooms and a senior center allowed them to maintain contact with friends.

"What we did was work with newly homebound senior citizens who used to participate in their senior center," she said, "and would likely never be able to leave the house again. Typically in that stage in life you lose your social contacts, and your health starts to plummet even worse."

The picture phones were used by four homebound seniors and were on at least five hours a day.

"All of the homebound people really, really liked it," she said.

Through their installation of The Tent, a multimedia art piece, John and Eva Waterworth of the Interactive Institute and Umea University in Sweden demonstrated how technology can create virtual environments that give users the illusion of being someplace else.

The tent they installed at Temple used an angled white screen, video cameras, four speakers, and a subwoofer to create a 3-D sound system.

One at a time, volunteers crawled beneath the sheet to recline on a mattress with a pillow containing four motion sensors so they could experience a seven-minute presentation titled "The Illusion of Being." Using sound, spoken and written words, computer animation, and video photography, the presentation is a multimedia collage evoking the cycle of seasons in northern Sweden.

Any slight movement by the viewer was picked up by sensors in the pillow, which determined the sequence and content of the presentation.

"The experience is unique depending on how you move," Eva Waterworth said. "People find it a very powerful experience."

Sarah Drury, an assistant professor of new media at Temple, was the first to crawl in.

"It was really wonderful," she said. "It's very similar to being in an Imax movie."

Because The Tent is so immersive, Eva Waterworth said, it could be used to reduce stress or to allow people who are severely disabled to experience things they are unable to do physically.

Tim Marsh, a doctoral student from the University of York in England, said that though much of the progress in virtual reality was coming from video-game developers, he was intrigued by The Tent and the possibilities of interactive media.

"It would be wonderful to develop environments that are cathartic, therapeutic and reduce stress," Marsh said. "I can see the day when we come home from work, get a beer, lie on the couch, get the interactive control, put the television on, and it is interactive. You can walk in environments. They don't have to be these shooter kind of games. You could be floating in the clouds or walking in a forest."

Matthew Lombard, associate professor of mass media at Temple, said that, having participated in earlier conferences in England and the Netherlands, he was eager to bring the event to Philadelphia.

Lombard said Temple was developing a media interface and network design lab to study "presence" - an experience created through technology that gives the participant the sense of being somewhere else. The lab will be connected to a network of university labs around the world that are working "to advance research in the area of cognition and technology," he said.

During the conference, scholars discussed their research on topics that included how to measure presence, its effect on virtual-learning environments and training simulations, and whether detailed computer graphics or text were more effective in drawing gamers into online competitions.

Some research suggests that text-based games may be more deeply involving because - as in a novel - players use their imagination to create a mental picture.

Amela Sadagic, a senior computer science researcher with Advanced Network & Services Inc. in Armonk, N.Y., described work being done with a team of academic researchers to find the ultimate synthesis of computer graphics and computer vision systems through what they term a "tele-immersion portal." The National Tele-Immersion Initiative aims to allow people in different locations to collaborate in "shared, simulated environments" using Internet2, the experimental, superfast computer network.

Researchers from the University of Pennsylvania are among those working on the project.

Though many of the presentations at the conference focused on narrow academic topics, participants said the research likely would have an effect on how we learn and play in the not-too-distant future.

"They can use the theory to design better products that people will use . . . in some cases, very soon," Lombard said. "In some cases, the theory applies to things that aren't possible yet, but that may be in the future. That is one of the things I like about [the field]. It is . . . forecasting where things are going."

www.temple.edu/presence2001