It is stunning to realize how often a witness confidently looks across a court room, points, and declares, “I was there. I saw it all, and I’m sure that he’s the one who did it,” only to be just plain wrong. Eyewitness identifications are powerful and compelling trial evidence, and yet DNA analysis has revealed that roughly three-quarters of this country’s known wrongful convictions for rape and murder have been based on erroneous eyewitness identifications. That’s an awful lot of sure, but mistaken, people. Research has proven time and again that this seemingly infallible sort of testimony is actually frequently wrong. This presents the obvious question: why are so many eyewitnesses so confident, yet so wrong? There seem to be a number of factors that contribute to erroneous eyewitness identifications.
First, there is the Catch-22 of whether the witness realizes the significance of what they are witnessing at the time that they witness it. If the event’s importance is not known at the time, the memory is unlikely to imprint accurately (can you accurately identify the person who stood behind you in line at your most recent grocery trip? or the person who sat next to you on the train last Tuesday?). But if the event’s significance is readily apparent – the witness sees a murder or experiences a rape or an armed robbery – then stress can often inhibit the ability to remember accurately. Study after study shows that anxiety and stress can decrease a person’s ability to accurately recall what happened. And, when you add the presence of a gun to the stress of witnessing a crime, the memory problems increase exponentially because of what is known as “weapon focus” – oftentimes, pretty much all the witness’s brain can focus on and process is the presence of the weapon, rather than the other details of the crime.
Then, there’s the problem of distorted memories. Like physical types of evidence, eyewitness identifications can be contaminated or destroyed, even inadvertently. Researcher Elizabeth Loftus has done loads of experiments to show how easy it is to taint a memory. For example, when witnesses in one experiment were asked about how fast cars were going when they “hit” versus how fast they were going when they “crashed,” the word choice had a strong impact on the witnesses’ memory of watching the event and, specifically, on their memory of how fast the cars were going. In some of Loftus’ experiments, she convinced numerous study participants that certain invented memories – getting lost in a department store, breaking a window, choking on an object, witnessing a drug bust – were true. What she found was that when presented with evidence of the false memory, people not only “remembered” the incident, their brains supplied fictional details to support it. In a more recent study, Loftus and colleagues took military personnel who had been confined to stressful, mock POW camps as part of their survival training and showed them false photographs, purporting to be their aggressive training interrogators. With that misinformation, more than half of these military professionals were no longer able to identify the interrogators at their own individual training session.
So, what does that mean for crime witnesses? It means that there are many ways that a witness’s identification of a perpetrator can be falsely altered: seeing the suspect in handcuffs; believing that other witnesses already identified the individual; believing that the perpetrator is definitely in the lineup; hearing subtle cues from the officers conducting the lineup (“Are you sure that’s the one? Take your time and look more closely…”); seeing a photograph of the accused before a lineup; hearing suggestive questions prior to the lineup (“The perpetrator wore glasses, didn’t he?”); etc.
The reality is that it is unbelievably hard to make accurate eyewitnesses identifications. Added to that generality are the frequently present inhibiting factors like distance, dim lighting, cross-racial identification challenges, brevity, and obstructed views, and it’s no wonder that there are such an astounding number of wrongful convictions based on faulty eyewitness identifications.
For more information, see an interesting TED Talk by Elizabeth Loftus on faulty eyewitness identifications…