To identify a suspect, police typically ask eyewitnesses to pick him out of a line-up of similar-looking folk. Alas, this method is often inaccurate. DNA testing has shown that witnesses often fail to detect the culprit or, worse, wrongfully accuse the innocent.
Why should this be? Witnesses may feel under pressure to identify someone as the guilty party, even if they are not sure. Or they could be worried about making a mistake. A new study suggests that witnesses will make more accurate identifications if they do not have to be so precise.
Neil Brewer, a psychologist at Flinders University in Australia, has devised a new type of police line-up, described in Psychological Science. Rather than simply pointing out the perpetrator, witnesses are asked how confident they are when identifying him. And they have to make up their minds quickly. Whereas a typical police officer tells a witness to take time and mull it over, Dr Brewer sets a very short deadline.
Dr Brewer knew from past research that strong memory traces are more rapidly accessed by the brain than weaker ones—and that accurate eyewitness identifications are made significantly faster than inaccurate ones. So he guessed that limiting the time witnesses had to look at suspects would yield better results.
Read the whole story: The Economist