We need an eyewitness

That's a common line in a crime drama.  But scientists are questioning the accuracy of eyewitness testimony, which comes some time (it could be years) after the event was witnessed.  

Take a study of people's memory of 9/11.  A very dramatic event.  A world-changing event.  Well, researchers from the New School and NYU have been tracking the recollections of people about the event. They started just after the event.  One year later 37% of the details had changed.

Or, look at the Innocence Project, which tries to free people who have been wrongly convicted.  75% of false convictions that are later overturned are based on faulty eyewitness testimony.

It seems that our recollections are always being altered, the details of the past warped by our present feelings and knowledge. The more you remember an event, the less reliable that memory becomes.

Neil Brewer, an Australian psychologist, thinks there is a better, more accurate way to get eyewitness confirmation of an event.  Give witnesses two seconds to make up their minds. Then ask them to estimate how confident they were about the suspects they identified, rather than insisting on a simple yes-no answer.  His results show a large boost in accuracy, with improvements in eyewitness performance ranging from 21% to 66%.  Even when subjects were quizzed a week later, those who were forced to choose quickly remained far more trustworthy.