However, that doesn't make the pedestrian/ treadmill experiment any less unique, Kaczmarski said. "This has never been done before, anywhere."

Kramer has been a pioneering researcher in the area of driver distraction, with several studies done in Beckman's driving simulator, located just down the hall from the CAVE. He said recent news stories about accidents on campus and around town involving pedestrians prompted this new project that will, like the driver studies, focus on the divided attention of test subjects who are using devices like cell phones.

"We thought that maybe we needed to go beyond driver distraction and start examining pedestrians and how distracted they get as they are crossing busy streets and whether or not it had implications for what happened to them," Kramer said.

The initial run-through session had Kramer, Neider, and Crowell brainstorming on final revisions to the experiment. After taking his turn on the treadmill, Kramer asks Crowell if the speed of the cars can be varied.

"We are kind of pushing the rendering power," Crowell cautions, concerned that increasing the complexity of the simulation might affect the ability to display the cars' movements smoothly.

"Are we able to record all the variables with respect to the simulated automobiles, walking speed, whether you're hit or not hit, where you start relative to where the car is and what the speed is?" Kramer asks.

Yes, they know the speed of the cars and can estimate the speed of the pedestrians, Crowell says.

"What about the distance of a car, say, when they enter the roadway?" Neider asks.

"Sure." The experiment's computer program can even save the test subjects' entire time course at half second or one second intervals throughout the whole course, Crowell adds.

Over the span of the next half-hour, the three discuss the experiment, including issues such as whether to use iPods and if so, what kinds of music (none know what kinds of music "the kids" are listening to so Neider suggests having grad students pick the tunes), or whether to have partners for test subjects if phone usage is studied.

Neider ticks off some of the possible distractions for the pedestrian test subjects: "You could have people just listening to music, you could have them listening to a podcast, or there is the possibility of a different kind of listening going on because they could be watching a TV show on an iPod. Or they could be talking on a cell phone."

Kramer takes things a step further. "We need to buy an iPhone," he says, drawing laughs.

The session ends with Kramer and Neider expressing satisfaction with the design; a little more tweaking and the experiment will be ready for student test subjects in September.

Turning a research idea into the reality of an experimental setting in the CAVE required months of back-and-forth discussions, numerous e-mail exchanges, and ideas that were suggested, cast aside or accepted. The run-through in August with Neider and Kramer was a sort of test-drive in order for Crowell to show the experiment's design to the researchers. While Crowell handled the computer and software requirements, it was up to Kaczmarski to integrate the treadmill into the experiment.

Kramer said there have been studies with treadmills that go at a certain speed but this one operates manually to recreate real-world walking conditions. Kaczmarski modified the treadmill by taking off the display on top and removing a magnet underneath that recorded the number of rotations; he then installed eight magnets that send signals to the PC cluster that powers the CAVE.

The CAVE lab, which had been moved from the third floor to its new home in the basement earlier in 2007, has been used as a testbed for experiments that would eventually be done in the Cube. Kaczmarski said the Cube has become so popular that ISL was forced to start using the CAVE as a facility for experiments, the first being this pedestrian distraction study.

Crowell, who has a Ph.D. in Cognitive Psychology from Cal-Berkeley, is just one of ISL's staff members who aid research efforts in human multimodal perception and cognition using the lab's advanced technologies.

Crowell's role for the past five-and-a-half years has been to assist researchers like Kramer and Neider in setting up experiments.