Eyewitness testimony plays a big role in many criminal trials in Minnesota courtrooms. Although the general public may believe that eyewitnesses provide strong evidence, many variables can lead people to make mistakes. Wrongful convictions often occur because of inaccurate witness statements.
Variables that influence eyewitnesses
Research on the quality of eyewitness testimony has identified issues, known as estimator variables, that undermine the idea that someone who identifies a suspect is always right. The variables are divided into three categories:
- Situational
- Target
- Personal characteristics of witnesses
A single variable or a combination of them could affect a witness’s accuracy. A situational variable could be available light or the distance between the witness and suspect. A target variable describes what a witness remembers about the person, such as height or hair color. Personal witness characteristics encompass eyesight or age that impact the ability to perceive details or distinguish between similar looking people.
System variables
On top of estimator variables, the actions and choices of law enforcement can influence a witness’s response. You are likely familiar with the system of a police lineup in which a suspect stands alongside other people and the witness is asked to identify the suspect. In this system, law enforcement exerts less influence on an eyewitness’s choice.
However, an alternative identification system can take place near the scene of a crime. This is known as a show-up. Police take someone into custody and ask the nearby witness or witnesses if this is the right person. In this system, witnesses may reply yes because they assume that police grabbed the right person in the immediate aftermath of the crime.
Show-ups should be reserved for emergencies
The National Institute of Justice determined that show-ups are best used for suspects of violent crime when society has an urgent need to take a suspect into custody. They are especially prone to error if police present a suspect to a group of witnesses. In the absence of other choices, witnesses may agree that this is the correct person. Anyone with doubts may give way to the group’s sentiment.