When it comes to making choices, say Caltech's Antonio Rangel
and his colleagues, much depends on which items catch—and
keep—your eye.
"We're interested in how the brain makes simple choices, like
which item to pick from a buffet table," says Rangel, professor of
neuroscience and economics. "Why is it that when we look at the
buffet table, our gaze shifts back and forth between the items in
order to make a choice? What is the role of visual attention in all
this?"
To find out, Rangel—along with Caltech postdoctoral
scholar Ian Krajbich and Stanford University's Carrie
Armel—designed a mathematical model to describe the impact of
what they call "visual fixation" on the making of these sorts of
choices. (Simply put, visual fixation is the amount of time you
spend gazing in one direction or at one item versus another.) They
recently published their research online in the journal Nature
Neuroscience.
"The model makes very specific predictions about how the pattern
of fixation is related to our choices," Rangel explains. "For
example, after controlling for other variables, items that are
looked at more should be chosen more often."
But are they? To make sure, the team carried out an eye-tracking
experiment in which subjects were shown pairs of food items on a
computer screen, allowed to look at the items for as long as they
wanted, and then were asked to choose one or the other. While the
subjects gazed, the researchers tracked the movements of their
eyes.
Just as predicted, the item a subject looked at longest was the
one he or she most often picked—nearly three-quarters of the
time, in fact.
Interesting stuff on its own merit, right? It also has
implications for the business world—putting increased
emphasis on things like packaging and in-store displays. "[T]he
model explains how cultural norms (for example, reading left to
right) can interact with comparator processes to produce cultural
choice biases," the scientists write. "These biases help to
explain, for example, why shelf and computer screen space on the
top-left is more valuable than other positions."
