Human recollections and accounts can be extremely compelling and convincing, but as many people in Media know, they can also be highly inaccurate. This may help explain why eyewitness testimony is one of the leading known factors in wrongful convictions. This evidence has played a part in a shocking 72 percent of false convictions exonerated through DNA evidence, according to the Innocence Project.
There are many reasons that eyewitnesses make mistakes, even in highly close or personal alleged crimes, such as sexual assault. Human memory is imperfect. Factors such as lighting, emotional distress, racial disparity and the presence of a weapon during the alleged crime can also affect an eyewitness’s perceptions and recollections. Police identification procedures can also influence eyewitness memories in subtle but harmful ways.
A recent report from the National Academy of Sciences highlighted the need for better protection against eyewitness errors. According to The Philadelphia Inquirer, the report notes that human memory is not a fixed recording; instead, it is vulnerable to losses, distortions and the power of suggestion. Information introduced after an event occurs may change the way an eyewitness remembers the event, without the eyewitness even realizing that any changes have occurred.
Given this risk, the report recommends that law enforcement authorities implement several changes to prevent “contamination” of eyewitness memories during identification procedures. These changes include:
- Conducting blind lineups with an administering officer who does not know the suspect’s identity – this can prevent the eyewitness from picking up on unconscious cues.
- Recording each identification – this creates a record that can reveal breaches in protocol or other issues later.
- Starting every identification with standardized instructions – the instructions should convey that the eyewitness does not have to identify someone and may not even see the suspect.
- Providing more training to authorities – authorities should receive instruction on gathering evidence from eyewitness and evaluating the veracity of eyewitness statements.
The report also recommends that courts create jury instructions that advise jurors of the potential inaccuracy of eyewitnesses. Alternately, courts may allow experts to explain the science of eyewitness evidence to jurors and judges. Furthermore, jurors should be informed of whether the identification occurred soon after the crime, when the memories of eyewitnesses tend to be most accurate, or later, when outside influences may have affected the eyewitness’s recollection.
Pennsylvania has already implemented one of these recommended measures. In 2014, the state Supreme Court ruled that people accused of crimes can call experts on eyewitness evidence to testify during their trials, according to the Delaware County Daily Times. In the past, such testimony was not permitted, under the assumption that jurors could judge for themselves whether an eyewitness was credible.
The court ruling provides guidelines on when this expert testimony is permissible, but the discretion to allow the testimony ultimately rests with each judge. Still, when this testimony is considered relevant and permitted during trial, it could make a considerable difference in the final outcome.
Challenging eyewitness evidence
In any criminal case that involves eyewitness testimony, the scientific evidence that shows this testimony can be unreliable should also be considered. People facing criminal charges based on eyewitness evidence may benefit from speaking to an attorney about the best way of calling attention to the potential issues with this evidence.