Eyewitness testimony is hugely influential in criminal cases. And yet, brain research has shown again and again that human memory is unreliable: Every time a memory is recalled it becomes vulnerable to change. Confirming feedback—such as a detective telling a witness she “did great”—seems to distort memories, making them feel more accurate with each recollection. Since the start of the Innocence Project 318 cases have been overturned thanks to DNA testing. Eyewitness mistakes played a part in nearly three-quarters of them.Another new technique is known as the "sequential" line-up, in which the witness is shown a series of photographs, one at a time, and asked after each if it is the perpetrator. This seems to reduce the number of false positives, but it also reduces the number of correct identifications; serial killer Ted Bundy was missed in a sequential line-up and went on to murder more women. So sequential vs. simultaneous line-ups is a trade-off, neither one perfect.
For three decades psychology researchers have been searching for ways to make eyewitness identifications more reliable. Many studies have shown, for example, the value of “double-blind” lineups, meaning that neither the cop administering the lineup nor the witness knows which of the photos, if any, is the suspect.
But there is one thing that all researchers agree on is
. . . the importance of recording the witness’s level of confidence immediately after making a photo identification. As many studies have shown, witnesses’ confidence in their memories tends to inflate over time, which is obviously problematic if they’re testifying in court long after the event took place.When you look in detail at cases of mistaken identification, you often find that the witness was initially unsure, and recording that datum can do a lot to protect the innocent without necessarily putting the police off from pursuing the guilty.