Thursday, October 9, 2014

Fixing Police Line-Ups

Virginia Hughes reviews the research on police line-ups, and attempts at reform:
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.

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.
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.

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.


G. Verloren said...

Eyewitness testimony isn't totally useless, but it certainly isn't nearly as trustworthy as we treat it. But we've known this for a long time - we just haven't had cheap enough, accessible enough DNA testing to confirm or deny individual cases of guilty. So much for innocent until proven guilty.

Of course, the nature of evidence collection is changing. Miniaturization of cameras and video recording devices may mean in the near future, people begin to record what they their eyes see for later perusal. The year may not be that terribly far off when we cease relying on biology for the reception and storage of visual data, and instead place our faith in personal technological implants or garments. One can only guess at how this might impact society at large...

pootrsox said...

A lot of what you references, G. V., is already beginning with the ubiquity of smart phones.

People start video'ing things they see that concern them, and the videos are far less subject to the failures of human memory :)

Also, cops wearing minicams protects them from faulty witness memory of perp-cop and innocent bystander-cop interactions.

John said...

That's why Bigfoot and UFO sitings are becoming less common. Everybody says, "You had your phone; where's the video?"

Shadow said...

I know memories can be suspect. I have to look no further than myself for proof. Those re-reads of books shock me; they are seldom as I remember. Still, some of the sketches produced from eye witnesses are uncanny. The one that comes to mind is the murder of Bill Cosby's son on the side of a road. All they had to go on was one witness' memory of his face, and they nabbed him. The sketch was so good. Of course, I'm remembering this, and that is a problem in itself. But, hey, some forensic "science" is junk science.

UFOs. When I was living is Vegas, we were always bombarded by area 51 stories. People would trot up there and watch strange things moving in the sky and say they were UFOs. I don't know what was actually going on, but I always wondered why their first thought would be UFOs, when this was going on over one of are more secret military bases.