New study calls attention to serious risk of flaws in eyewitness memory

Eyewitness testimony can play a decisive role in Chicago criminal cases; jury members often find this form of evidence especially compelling. Unfortunately, human memory is imperfect, which means the recollections of eyewitnesses can be flawed as well. A recent report calls attention to the danger of putting too much confidence in the testimony of eyewitnesses during Illinois criminal cases.

Dynamic nature of memory

The National Academy of Sciences report explored several factors that can influence the accuracy of eyewitness memory and raise the risk of misidentifications, according to the Washington Post. Even if vision factors are optimal and an eyewitness can properly see the perpetrator — which is often not the case — the nature of memory can still lead to inaccurate recollections.

Contrary to widespread belief, a person's memories are not fixed or static. Instead, memories change to reflect new information or experiences. Memories may be lost, rebuilt, updated or otherwise altered when they are processed, stored in the brain or later retrieved. People are unaware of these ongoing changes and often believe that clear or vivid memories are highly accurate.

Certain law enforcement procedures only enhance the risk of a person's memories becoming corrupted. When identifying a suspect in a lineup, an eyewitness may pick up unwitting cues from police officers who know the identity of the suspect. During trial, an eyewitness who was hesitant at the time of the identification may become more confident, due to feedback from authorities and others.

The NAS researchers support blind lineups as well as confidence statements, in which a witness describes his or her confidence in the identification at the time that it is made. According to the Innocence Project, Illinois has passed legislation requiring authorities to conduct blind lineups. This is an important step toward reducing external influences on eyewitness memories.

Still, the NAS report calls attention to the fact that, even with ideal law enforcement procedures, the use of eyewitness testimony still introduces an unavoidable risk of inaccuracy.

Uncontrollable variables

Sometimes, the way an eyewitness recalls an incident may be flawed from the beginning. Various factors can affect a person's ability to accurately take in and remember a scene, according to Scientific American. These factors include:

  • The presence of a weapon. This distracts witnesses from the perpetrator and enhances stress.
  • Strong emotions. Witnesses who are under severe stress during the crime or identification are more likely to make mistakes.
  • Racial differences. A witness is more likely to wrongly identify a suspect of a different race.
  • The suspect's appearance. Witnesses may also misidentify suspects who use disguises or simply lack memorable features.

These findings suggest that there is no protocol that can fully ensure the accuracy of every eyewitness. Sadly, this means misidentifications and mistakes will likely continue occurring in some cases involving eyewitness-based evidence.

Anyone facing criminal charges, especially in a case involving eyewitness evidence, should speak with an attorney as soon as possible to determine the most effective way to handle those charges.