- The misinformation effect occurs when an eyewitness subsequently reads or hears information about the witnessed event that is inaccurate and unwittingly incorporates it into his or her own memory of the event.
- Groups who are more vulnerable to the effect include very young children and the elderly; persons with a history of memory and attention lapses; persons with weaker perceptual abilities; and persons with more cooperative personalities or strong fears that others will think negatively of them.
- The effect can be minimised with timely interviews, so that exposure to misinformation is limited, and with a style of interviewing known as the ‘cognitive interview’.
Twenty-five people died in Los Angeles in 2008 during an incident in which a passenger train crashed into a freight train. The incident lead to a law suit in which the key issue was whether the deceased driver of the passenger train drove through a green light prior to the crash, or whether he drove through a red light, distracted by text messaging.
Four eyewitnesses (a conductor, a security guard and two train watchers) gave evidence that the light had been green. However, after a comprehensive investigation, the authorities decided the eyewitnesses were wrong (Jennifer Steinhauer, ‘At Least 18 Killed as Trains Collide in Los Angeles’, The New York Times (online), 12 September 2008 nytimes.com/2008/09/13/us/13crash.html).
Could four witnesses, giving consistent information about such a crucial matter, all have been wrong?
In fact, multiple eyewitnesses, each trying his or her best to provide accurate evidence, can all be wrong, even when they claim to have seen the same thing. Research in psychology over the last century has consistently suggested that eyewitness evidence lacks reliability. Of course, not every eyewitness gives unreliable evidence, but there are a variety of circumstances in which the accuracy of eyewitness evidence can fairly be called into question.
One such circumstance is widely referred to in the literature as the misinformation effect.