Police line-ups and psychology: Unusual suspects

Who’s the bad boy then?





To test this hypothesis, Dr Brewer and his colleagues asked 905 volunteers to watch a series of short films. The volunteers were told to pay close attention, since they would be asked questions about what they had seen. Each film showed either footage of a crime (eg, someone shoplifting or stealing a car), or a seemingly mundane series of events such as people using a cash machine. For the latter, volunteers were told that one of the people in the film was a suspect in a crime that had occurred nearby and that they would be asked to help identify him.

Half the participants—some a week later, others within five minutes—were then shown, on a computer screen, a series of individual pictures from a line-up of 12 people. The witnesses saw each face for three seconds; after two seconds a buzzer went off, indicating that they had to complete their identification in one second. To do that, they had to click on one of 11 on-screen buttons ranging from “100% confident that this is the culprit” to “0%, absolutely certain this is not the culprit”. If they were too slow, the next face appeared.

The other half of the participants were shown the same faces one at a time, but were given as long as they liked to answer. The results were analysed using a statistical test. The witnesses who were given a flexible choice but only a short time to ponder were much more accurate. They picked the correct suspects 67% of the time. The “yes or no” group picked the right man only 49% of the time. A witness delayed may be justice denied.

Ghana Politics Today
