The cover of the Dec. 4 issue of Current Biology features breakthrough research in optic flow conducted by William Warren, professor and chair of the department of cognitive and linguistic sciences. Warren and his team conducted the research at the University's Virtual Environment Navigation Lab - located in Metcalf Research Laboratory, the 12-meter by 12-meter lab is one of the largest virtual reality labs in the world.
Optic flow is the motion pattern created at the eye when people move through the world, Warren said. When people move toward a specific point, motion appears to radiate out from that point and conveys information about the direction in which the person is moving.
Warren's lab uses virtual technology to test theories on optic flow by controlling the laws of optics.
"Virtual reality is great because it allows us to manipulate the visual information that people are getting when they actually walk around," Warren said.
The lab focuses on studying how people use perception to guide their actions, especially locomotion, Warren said. The current research at the lab uses walking as a test case. When people are standing still, they have two ways to navigate toward an object in the distance, Warren said. They can simply start walking in the direction of the door, using visual direction, or they can begin to move and use optic flow to test their direction, since optic flow should radiate out from the object toward which they are traveling.
VENlab used two virtual settings for their research, according to Warren. One setting used a prism that bent light with a simulated door at the end, creating a rich environment for optic flow. The other setting was a straight-line environment that lacked surrounding flow. Subjects were supposed to walk toward the door, but the alteration was that the lab displaced the direction of optic flow 10 degrees to the right, making the door appear farther to the right than it actually was. In order to reach the target successfully, subjects had to adapt by walking slightly to the left to realign the optic flow with the direction of the simulated doorway.
Hugo Bruggeman, a postdoctoral research fellow who headed the experiment, discovered that individuals quickly adapted to walking slightly left of the target in order to reach the door when optic flow was available to them. A November press release said these subjects were usually able to make it to the door by the third trial. Subjects in the line environment without optic flow took approximately seven times longer to adjust, Bruggeman said.
The results of the research have a practical use in robotics, Bruggeman said. The knowledge of how humans use optic flow to guide perception can help in the formation of "robust steering algorithms" that tell robots to align the center of optic flow with their targets. Scientists can use such information to translate to robots qualities of the human perception necessary to convey visual information into locomotion. Warren's lab will continue future studies to develop their ideas of human perception and the brain.
"Basically, we have to acknowledge that the brain is very much a leaky system," Bruggeman said. "It requires continuously new information to be updated."
The team is focused on studying the role of the brain and re-evaluating the models currently used to explain its functions and its role in its environment.
"The deep insight here is that we normally think of the brain as controlling things," Warren said. "But really the brain is situated in an environment and it's got to use information from the environment. It's not that the brain structures our behavior, it's as much the environment structures the brain. It's really a continuous loop."
The results of VENlab's current research has opened multiple doors for further studies because of the "endless problems" and questions the results have shown about the complexity of human behavior, Warren and Bruggeman said.
"We're really at the start of trying to understand the brain," Bruggeman said.
