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The editor of the flagship journal Psychological Science, in which Nawrot’s research was published, noted its importance. He called it “a near perfect blend of an applied and theoretical advance. … ” A peer reviewer commented that “results are of impor- tance on theoretical grounds. … and are also of practical importance because they provide additional evidence about a specific type of deficit alcohol can induce in a drinking driver.”

That connection between depth perception, alcohol and driving made headlines. “Perceptions: Drunk, and Out of Your Depth” appeared in the New York Times. “Alcohol impairs depth perception” said CNN, the Canadian Broadcasting Corporation and the BBC in the United Kingdom. “It’s all Greek to me,” was the subject line in one e-mail that contained a story from a publication in Greece. It was only the beginning. Research results discovered by the team at NDSU’s Center for Visual Neuroscience appeared in media around the world, with information published in German, Russian, Spanish and Italian. “Why drunk ones more frequently against lantern stakes drive,” was one headline translated from a German publication’s Web site. Publications in Slovenia, India, Turkey and Asia covered it. Nawrot also received media inquiries from Ireland and Switzerland.

He is pleasantly surprised by the attention. The pages of the New York Times reach a different audience than that of scholarly journals. “I still find it funny that the words ‘motion parallax’ could appear in the general press. Drunk driving must be an issue in many countries,” he says. A news release summarizing the study found its target audience shortly before New Year’s Eve by mentioning statistics from the U.S. National Highway

Traffic Safety Administration which showed that from 1998 to 2003, on New Year’s Day, 42 percent of fatalities involved a drunk driver, compared with 31 percent during the entire year.


Although experiments were con- ducted in a lab, they offer another clue as to why drunk drivers are likely to be dangerous. At a blood alcohol content approaching 0.1 percent, motion paral- lax became at least 4.5 times worse. “Participants were nearly motion parallax blind,” says Nawrot, giving additional meaning to the phrase “blind drunk.” This aspect of alcohol intoxication was previously unknown. “In addition to well-known problems such as impaired decision-making, poor coordination and balance, the study shows that intoxicated drivers have difficulty judging the relative depth of objects that they are trying to avoid while driving.”

It may be only one part of a broader, but less understood, set of visual per- ceptual problems caused by alcohol on the eye movement system. Study of alcohol’s effect on eye movement could lead to a better understanding of the precise blood alcohol levels at which drivers become impaired, says Nawrot.


Research into the role of eye move- ments in motion parallax is relatively new. Only four studies have been pub- lished on the subject, three of them by Nawrot, in the Journal of Vision and Vision Research. It’s only relatively recently that researchers have been able to look at eye movements, he says. Earlier equipment to measure them was cumbersome and expensive. The technology progressed and the cost of equipment decreased. “It was the right idea at the right time with the right technology.”

An overnight success, if you will, after eight years. Patience is a virtue, as our mothers once told us. Ask any researcher. Nawrot estimates it took methodical, detailed, continual research over four years to develop the new theory of the role eye move- ments play in depth perception. His recently-completed study funded by the National Institutes of Health’s National Eye Institute was a way to test that new theory. Disrupt the eye movement system with alcohol and measure the effect on the perceptual system. Initial design of the motion parallax study and the actual experi- ments took two years. Add another year to analyze the tremendous amount of eye movement data. Tack on another year for peer review and publishing of results.

Still, Nawrot’s enthusiasm doesn’t wane. He acknowledges the complexity of that relationship between the brain and the eyes results in more questions than answers. “I’ll grab a brain here,” he tells a visitor, locating a plastic model in his office for a more detailed 3-D example. “The frontal eye fields are one region that receive and feed information to other brain and brain stem areas for eye movement,” he says, cradling the model in his hands. “The movements themselves are driven by nerves coming out of the brain stem. There are just twelve pairs of cranial nerves in the brain and one-third of them are involved with vision and eye movement. We have another twenty or thirty years of study to go on this.”

  • Carol Renner


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