Eyewitness statements should be taken with a grain of salt, report finds

A recent report questioned the reliability of eyewitness statements.

If you regularly watch television crime dramas, you often see that the testimony of an eyewitness is very influential on the jury when it comes to determining guilt or innocence. In real life, eyewitness testimony is also powerful evidence in virtually all criminal cases. However, recent research into human memory has indicated that eyewitness testimony is not as reliable as you may think, due to how the brain works.

The National Academy of Sciences (NAS) recently released a report on this subject. In compiling this report, researchers examined 30 years of studies of how memory plays a role in identifying suspects. The report found strong evidence that even in the rare cases where people can clearly see a suspect or event, they often have inaccurate recalls of it later, due to the changeable nature of memory. As a result, the report suggests that eyewitness testimony should not be conclusive in determining guilt or innocence.

The NAS report confirmed that the nature of memory is not static and unchanging. Instead, the brain periodically modifies, forgets, distorts or adds information to the memory of a person or event. This can occur at every stage of processing, from the time that the person or event is witnessed to when it is ultimately retrieved. In almost all cases, the report said that the person is unaware of these changes, and remains confident in the accuracy of the memory despite these modifications.

The report also noted that several types of external factors can work to influence a person's recollection of a person or event. For example, strong emotions, duress and the presence of weapons during the witnessing of the crime can significantly increase the risk of an inaccurate recollection. Likewise, the presence of any prejudices (e.g. racial) in the beholder of an event can also color the memory. Finally, if the suspect lacks any distinguishing features (e.g. tattoos, scars, etc.) it makes it much more likely that a witness will later make an incorrect identification.

In addition to these factors, the report noted that feedback from law enforcement has a significant effect on witness memory. During the identification process, uncertain witnesses may pick up subtle cues about the alleged perpetrator's identity from officers and other authority figures, adjusting their "memory" of the event accordingly without knowing it. To prevent this, the report recommends that police departments use blind lineups. In this type of lineup, anyone present at the identification does not know the identity of the alleged perpetrator. This prevents the witness from being "tipped off."

Aside from blind lineups, the report recommends that police should take confidence statements before questioning eyewitnesses. This statement allows the witness to describe how confident they are in the accuracy of their description before it is influenced by other factors. If a witness significantly changes their description later, the confidence statement could be later used at trial to discredit the witness.

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Although the Dallas Police Department has already made blind lineups a routine part of their procedures, it is not currently standard practice for all departments. Even if this were the case, the report noted that there is no known way to completely guard against witness misidentifications, due to the fluid nature of memory.

The findings of the report highlight the importance of having an experienced criminal defense at your side when charged with a crime. An attorney can review eyewitness statements to identify contradictions and inconsistencies and work to secure the most favorable outcome possible on your behalf.