SPOKANE, Wash. – A team of researchers at Washington State University has received a three-year, $895,558 grant from the U.S. Department of Defense's Office of Naval Research to study the effects of fatigue on attention, decision making and their underlying biology. The study is part of a continuing line of WSU research looking at the effects of sleep deprivation on cognitive functioning.
The study may lead to more efficient staffing of Navy ships and other around-the-clock operations or safety-sensitive work environments.
The study takes off on earlier work that yielded two new findings, said principal investigator Hans Van Dongen, a research professor with the WSU Sleep and Performance Research Center. He and his collaborators showed that how we respond to sleep deprivation differs from person to person, based on our biology.
They also discovered that it depends in part on the task we're trying to perform. One person may handle sleep deprivation well in one task but badly in another. The reverse may be true for someone else.
"So how do we know how someone will do on a task that is operationally relevant but that cannot be readily practiced, such as decision making under challenging circumstances?" said Van Dongen.
To find the answer, Van Dongen teamed with: cognitive scientists and longtime research collaborators John Hinson and Paul Whitney, both professors of psychology in the WSU College of Arts and Sciences; military operational task expert Bryan Vila, a professor of criminal justice and criminology in the WSU College of Arts and Sciences; and Dr. Matt Layton, a clinical associate professor of medicine at WSU and the physician of record for the study.
The research team designed an experiment that will look specifically at the effects of sleep deprivation on distinct attention systems that can be separated out.
Whitney said that when making decisions based on information that comes in over time, people generally use one of two strategies to focus their attention: a bottom-up strategy, in which they wait until they have all information and can compare the earlier with the later; or a top-down strategy, in which they use early information to make a decision and use later information to confirm the accuracy of that decision.
During the experiment, study participants will complete laboratory attention tasks before, during and after a period of sleep deprivation to determine whether they tend to use a bottom-up or top-down attention control strategy. Based on the participants' performance, the researchers will predict their response to a set of deadly force judgment and decision making scenarios while sleep deprived.
The scenarios will be played out in the Sleep and Performance Research Center's simulation laboratory, which contains two high-fidelity shooting simulators. Depending on the scenario, the use of a firearm may or may not be justified.
"When people must rapidly determine whether deadly force is warranted, they may be primed to shoot or not to shoot, depending on the circumstances," said Whitney. "For those people who are top-down processors, when they make an error, we think it's going to be more likely an error of shooting when they shouldn't have shot. People who are bottom-up are more likely to make an error in the other direction—they may hold off to wait for more information until it's too late."
The researchers will use data to enhance an individualized fatigue prediction model they are developing to enable task-specific predictions of fatigue-related performance impairment. They will also look for genetic markers that explain the individual differences in how people respond to fatigue for the top-down and bottom-up control strategies.
Van Dongen said the study ties together a decade of collaborative work on different but related tracks to address questions of individual differences in vulnerability to sleep loss, all the way from the laboratory to the operational world.