The Eyes Have It
July 5, 2002
What distinguishes a .348 hitter like Barry Bonds of the San Francisco Giants from a so-so .230 batter with similar physical abilities?
Are good drivers doing something that eludes others who frequently have fender-benders?
Can poor readers find out where their critical points of difficulty lie and correct them?
For the athlete, driver and reader - along with people interested in marketing, web design, animation and other applications - the difference between excellence and mediocrity might be found in the eyes. Scientists believe the best hitters fix their eyes on an approaching ball milliseconds longer than less-successful players. Drivers who never have accidents could be using their eyes to scan the environment and react to hazards differently from those whose automobiles show scars of a less-focused view of the road.
Students who have difficulty reading might be able to pinpoint critical moments when their eyes stumble, allowing them to correct poor reading habits.
Researchers have been able to detect such distinctions - by measuring eye position up to 240 times per second - with the use of sophisticated eye-tracking software, cameras and computer equipment.
"An eye tracker is a camera that records reflections of infrared light off the eye," explained Elizabeth Crawford, assistant professor of psychology at the University of Richmond. "The relative positions of these reflections reveal where someone is looking." Crawford and several colleagues recently received a $13,600 grant from the National Science Foundation, matched by the university, to purchase eye-tracking software, computers and cameras. She and two undergraduate students, Josh Carlton of Roanoke and Dan Ahrens of Hamilton, N.Y., are using the equipment this summer to track how people view and remember emotionally evocative stimuli, such as photos of sharks, cute animals, beautiful landscapes or snakes.
"By measuring eye fixations, which may be as brief as 100 milliseconds, the equipment provides an online measure of human information processing," Crawford said.
Another University of Richmond psychologist, Ping Li, plans to use the eye tracker in his cognitive science lab in the fall to study reading comprehension.
"Because the eye tracker can accurately time-lock the reading event as the eye moves through the text, we can collect data related to the amount of time the eye spends on each word," he said. Readers can then identify critical points where they encounter difficulty, such as ambiguous words.
"We will also test children's reading comprehension with this equipment, which will allow us to see the development of reading habits," he added.
Craig Kinsley, psychology chairman at Richmond and a specialist in neuroscience, will use the equipment to determine how mothers-to-be view images of babies.
"Since the device monitors eye movements associated with interest, motivation, curiosity and emotional content," said Kinsley, "I will look at differences in they ways in which individuals with and without parenting experience view the images. How long do they linger on the eyes or the face or the hands of the infant?"
Kinsley also will note whether subjects pay more attention to the image of a crying infant than a non-crying one and will compare reactions of males and females when presented with images of babies. Kinsley, who has done extensive research on parental rats, is interested in using the eye tracker to extend his data to humans.
Other applications outside academia for using eye-tracking equipment include marketing, allowing advertisers to determine how long viewers' eyes remain focused on a particular ad or part of an ad; and animation and web sites, showing creators which parts of a screen viewers show most interest in.
"Although eye tracking is being increasingly used for research in psychology, engineering, human factors and education, students at primarily undergraduate institutions rarely gain experience with it," Crawford said. "Our eye-tracking lab will give students a greater understanding of advanced research methodologies in psychology and preparation for advanced study and deeper understanding of mind, brain and eye."