person scanning baggage or X-rays stands a better chance of seeing everything
they're searching for if they aren't feeling anxious, according to a new laboratory
psychologists put a dozen students through a test in which they searched for
particular shapes on a computer display, simulating the sort of visual
searching performed by airport security teams and radiologists.
Mitroff, an assistant professor of psychology and neuroscience who led the
experiment, says this area of cognitive psychology is important for improving
homeland security and healthcare. He's begun collaborating with the
Transportation Security Agency at RDU airport and radiologists at Duke.
earlier studies of this type, Mitroff's team had wondered if the anxiety
produced by being visible to a long line of frustrated travelers or having to
interpret an image in a medical emergency might change a person's performance
on these sorts of tasks.
simulate a stressful situation in this study, the researchers told the
participants they might receive an unpredictable electrical shock for half of
the trials that would be unrelated to their performance. Annoying but not
painful electrical shocks are a well-established means of inducing anxiety in
the lab. Only tests run without a shock were analyzed, focusing the research on
the anxiety produced by anticipating a negative event. On the other half of the
trials, participants heard a harmless tone.
performed about the same when searching for a single object whether anxious or
not. But when the researchers added a second target, participants were more
likely to miss the second object when anxious, despite spending the same amount
of time looking at the image.
a second target is a well-known issue called "satisfaction of
search," Mitroff said, and it's believed to account for about 40 percent
of radiology misses. A person finds the first object and then simply fails to
see the second one, even though they're still looking.
heightened the satisfaction-of-search problem, a finding which has important
implications for the way we train and test searchers, Mitroff said.
research appear early online June 13 in Psychological Science. It was was
supported by the Army Research Office and the Institute for Homeland Security Solutions.
anxiety hinders detection of a second target in dual-target search,"
Matthew S. Cain, Joseph E. Dunsmoor, Kevin S. LaBar and Stephen R. Mitroff.
Psychological Science, June 13, 2011. doi:10.1177/0956797611412393