If you were the victim of a crime, how good of an eyewitness do you think you would be? Would you be to identify the perpetrator(s)? Would you be able to remember what they were wearing? What color was their pants or shirt, were they wearing a hat? What did they look like… how tall were they, did they have any facial hair, what color were their eyes, hair, and skin tone.

Unfortunately, eyewitness misidentification is widely recognized as the leading cause of wrongful conviction in the United States. Of the 250 cases overturned through DNA testing 75% of those convictions were based on eyewitness testimony. This accounts for more wrongful convictions than all other causes combined. In case after case, DNA has proven what scientists already know – that eyewitness identification is frequently inaccurate.

Eyewitness identification can be useful in the initial stages of an investigation to help narrow down the suspect pool. But sentencing a person to serve prison time or even worse death, based purely on eyewitness testimony in my opinion, is just plain wrong. Forensic science is by far more reliable than any eyewitness can be.

Why is eyewitness identification unreliable?
Just as trace physical evidence (such as DNA or fingerprints) can be contaminated if it is not collected correctly and carefully, so too eyewitness evidence can be spoiled if it is gathered in ways that do not properly control for known sources of error. There are several factors that can contribute to eyewitness misidentification of a criminal. Some of those are:

Poor Lighting Conditions
Many crimes are committed under the cover of darkness because criminals know there is less chance they will be seen and identified. Lighting can be a big factor in identification. Under certain lighting conditions, a dark blue jacket could appear to be black, and a white vehicle could appear yellow.

State of Mind
During the commission of a crime, victims are often under severe stress which can affect their thought process and their ability to remember detail. Their primary goal is to survive, remembering details is secondary.

Physical Trauma
If a witness suffered a brain injury during an attack, they may not be capable of remembering any details as those memories may have been permanently lost.

Imperfect Memory
Unless you were born with an eidetic memory, chances are you probably can’t remember what you had for breakfast last week Tuesday. The simple fact is that as time passes, people tend to forget details. The more time passes the less detail we can remember. In some instances you can actually remember incorrectly. However, research has shown that memory is highly malleable, and that an eye witnesses that is uncertain can become more certain of themselves over time.

Influence
Often people’s memory can be influenced by circumstances or other people. If a person is asked to pick a criminal out of a photo lineup  of 6 individuals, the witness may feel obligated to pick one of the 6 photos even if the witness isn’t certain person that committed the crime was in one of the photos. If the witness is only 80% certain that one of the photos was the criminal. If the witness’ choice is positively reinforced buy investigators who had already suspected the person that was chosen, that can boost the witness’ confidence in their choice. If they are later asked to identify the criminal out of a physical lineup, and the only person from the original photo lineup was the person they originally chose, then that can serve to increase the victims confidence yet again. By repeating only one suspect in multiple procedures it increases witness confidence in their choice even if they are wrong.

Can the witness identification program be improved?
Yes. By having specific procedures in place during eyewitness interviews, it can limit the possibility for influence. The person who administers any lineups should not know the identity of the suspect. This procedure prevents well-intentioned officials from giving
inadvertent clues to the witness which could influence the witness decision or confidence. The lineup members should be presented to the witness “sequentially” (one at a time) rather than simultaneously (all at once). Presenting the lineup members one at a time to
the witness reduces the tendency for witnesses to engage in “comparison shopping.” Instead, the eyewitness must decide whether each individual lineup member matches her memory of the perpetrator, as opposed to making a relative judgment.