Study: It really does hurt to wait

From CNN.com

Anyone who's ever taken a preschooler to the doctor knows they often cry more before the shot than afterward.

Now researchers using brain scans to unravel the biology of dread have an explanation: For some people, anticipating pain is truly as bad as experiencing it.

How bad? Among people who volunteered to receive electric shocks, almost a third opted for a stronger zap if they could just get it over with, instead of having to wait.

More importantly, the research found that 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, the things people will do for positive outcomes.