On the first floor of Dyer Hall at the University of Cincinnati is a room that moves.

Thomas Stoffregen, associate professor of psychology, designed the moving room to test his new theory about motion sickness -- a theory that has attracted a lot of attention, and criticism.

Working under grants from the U.S. Navy, Stoffregen created a large plywood "room" which moves on tracks to allow scientists to study human perception in a dynamic (more natural) environment.

The Navy is looking for answers about why some pilots get motion sickness while training in stationary flight simulators. What was perplexing to the Navy is the sophisticated, but stationary, simulators were far more likely to make experienced pilots nauseous than rookies. It was not the realism of the simulator that made veteran pilots ill, Stoffregen said. They do not get motion sickness while actually flying jets.

But that phenomenon was not surprising to Stoffregen. According to his theory of motion sickness, published several years ago, we all "wobble," so to speak, at a particular frequency. Whether sitting or standing, we are never perfectly still. There is a natural postural sway of the head, and different people naturally sway more or less.

Just like water waves in a high school physics experiment, the frequency of natural sway interacts with the frequency of environmental moving systems. Just like in the wave tank, those waves can cancel each other out, accentuate each other or pass right through each other without effect, depending on the frequency of the postural sway and of the external phenomenon.

In his moving room, Stoffregen uses sensors to record subjects' postural sway, first the natural sway when the room is stationary, and then while it is in motion. He moves the room at different frequencies to find out when motion sickness occurs.

Stoffregen s work confirms that the frequency of human postural sway is between 0.1 Hz. and 0.5 Hz. The frequency of motion from ocean waves, ship motion, aircraft motion, flight simulators, and car travel all overlap with the frequency of people's natural sway.

Stoffregen has analyzed data from Navy experiments in which sailors are shaken up and down in a simulator at different frequencies and acceleration. Those experiments also show 0.1 Hz. to be the key threshold for humans to experience motion sickness.

Stoffregen's work has increased his visability in his field. Researchers in 40 nations have requested reprints of his major paper on postural sway. (Riccio, G. E., & Stoffregen, T. A. (1991). An ecological theory of motion sickness and postural instability. Ecological Psychology, 3, 195-240.)

Since then he has published ongoing findings in "Experimental Psychology" and "Behavioral and Brain Sciences." Two additional reports are now being drafted for fall publication. This year, he also was named to the editorial board of Ecological Psychology, the premier journal in that field.

In December, Stoffregen was invited to lecture at the University of Tokyo. Also a colleague from Canada and a French graduate student have each spent months on campus studying in his lab.

Another theory Stoffregen published recently, on how animals like bats and dolphins find their way back to the same location, last fall brought an invitation to collaborate at a dolphin research institute in Hawaii. "You never know what you'll get when you present a theory."

Although ecological psychology first appeared in the 1940s, it was only in the past 15 years that the field has made inroads into mainstream research because of its practical approach to the study of human behavior which has made it important in the study of ergonomics, improving productivity and even virtual reality.

"Ecological psychology is a general theory, almost a theory of behavior," Stoffregen said. "It is a theoretical strategy that is incompatible with other theories of perception." That is probably why the criticism became rather vitriolic when he first published his theory of motion sickness.

Psychologists have traditionally approached behavior from the standpoint of information processing. In that approach, you might create an experiment in which you show subjects a ball, and then ask them to describe what they saw -- when they saw it, its color, texture, size. The difference with information processing research is that there is no action involved.

With ecological psychology, the interest is how people interact with their environment. It is an evolutionary theory that approaches perception as a way that people can perform better, Stoffregen said. For that reason you are more likely to toss the ball at the subject and record how he or she catches it.

The next step in his research will be a collaboration with Benoit Bardy, who is on the sports sciences faculty at University of the Mediterranean in Marseilles, France. He has achieved similar results to those produced by Stoffregen s moving room using virtual reality simulations on a big screen TV.

"We can ultimately learn what can and cannot be simulated," said Stoffregen. "Some people are trumpeting that we can use virtual reality to do anything, but there are things that cannot be simulated."
Background papers