How much attention the brain pays to expected pain determines whether someone is an "extreme dreader" -- suggesting that simple diversions could alleviate the misery.
The research, published in the journal Science, is part of a burgeoning new field called neuroeconomics that uses brain imaging to try to understand how people make choices.
Until now, most of that work has focused on reward: things people will do for positive outcomes.
Dr. Gregory Berns of Emory University, who led the new study, told The Associated Press, "We were interested in the dark side of the equation. Dread often makes us make bad decisions."
Standard economic theory says people should postpone bad outcomes for as long as possible, because something might happen in the interim to improve the outlook.
The MRI scans showed that a brain network that governs how much pain people feel became active even before they were shocked, particularly the parts of this "pain matrix" that are linked to attention.
