History is filled with examples of tragedies that turned out to involve sleep-deprived personnel, like the Chernobyl nuclear power plant meltdown, the grounding of the Exxon Valdez oil tanker, and the explosion of the space shuttle Challenger.

But research has consistently shown that although sleep loss degrades attention, its effects on decision making appeared to be relatively small.

So Washington State University researchers designed a laboratory experiment that stimulated how sleep deprivation affects critical aspects of decision making in high-stakes, real-world situations.

Twenty six participants participated in the research. For six days and nights, they lived in a hotel-like laboratory where they performed specially designed tasks to test their ability to use feedback to guide decisions. Half the group was not allowed to sleep for two days while the other half of the group was allowed to rest.

They were shown a series of numbers that, unknown to them, were assigned to have either a "go" (response) or "no go" (non-response) value. They had less than a second to decide whether or not to respond to each number shown. Then, just when they had become accustomed to how the test worked, the researchers switched the “go” and “no go” responses.

The rested participants were able to catch on, but the switch confounded those who were sleep deprived.

"People in high-stakes environments are held accountable for their actions when they are fatigued just like everyone else, however we now know that when someone is sleep-deprived their brain simply can't process feedback from their actions and changing circumstances,” said Hans Van Dongen, director of the WSU Sleep and Performance Research Center at WSU Spokane.