Sallyport - The Magazine of Rice University - Winter 2002

The Eyes Have It - Through the Sallyport
Winter 2002
VOL.58, NO.2
The Eyes Have It
When a new window or webpage pops up on your computer screen, what
do you look at first? Michael Byrne, assistant professor of psychology at
Rice, might be able to tell you. He has developed a model of human
thinking and performance that can predict how well people locate and
select various options on a computer screen. The model has implications for
designing air-traffic-control monitors, in-car navigation systems, webpages,
and other computer displays to present on-screen information most
effectively to the viewer.
“Our theory and model allow scientists to make predictions about human
performance on tasks that involve computer displays,” says Byrne. “We can
tell, for example, where to position information on a computer screen so
that the user is more likely to see it quickly.” Byrne conducted the research
at Carnegie Mellon University before joining the faculty at Rice, where he
analyzed the results that are published in the July issue of the International
Journal of Human Computer Studies.
“Understanding the interaction of a user with a designed device like a
computer requires a clear understanding of three components,” Byrne says.
“The user’s cognitive, perceptual, and motor capabilities; the task; and the
device used to accomplish the task can impact the result.”
Byrne showed each of the 11 participants in his study more than 100
questions that involved identifying a particular number or letter in lists of
random numbers and letters on a computer screen. He timed how long it
took the participants to spot the selected symbols. A camera mounted on a
headband worn by the participants tracked their eye movements.
Using a theory of cognition known as ACT-R/PM and an eye-tracking
model, Byrne predicted how long it would take the participants to click on
the targeted items. He also predicted the other items they would look at en
route to the targeted items, based on the characters or numbers they were
likely to fixate on and the order in which they were likely to read
information on the display. Byrne found that his predictions averaged
within 15 percent of participants’ actual response times—“close enough to
be useful to designers,” he says.
Engineers who design air-traffic-control monitors, for example, could use
the theory and model to position critical information on a screen where the
user is most likely to see it first. “Keeping up with the volume of
information on a computer display is often a problem,” Byrne said. “A
designer can optimize the rate at which people can process information on
the screen by using the theory and model we studied. A strategic placement
of menu items can make it possible for people to read the most important
information fast enough to keep up with their work so they don’t end up in
a situation where they’re likely to make errors.”
Byrne’s research was supported by the National Science Foundation, the
Office of Naval Research, the National Institute of Mental Health, and
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