People generally understand that human memory is not fool-proof. Long-term and short-term memory has shortcomings that can make it hard to remember certain details about a person or a situation.

When those details are involved in a criminal trial, however, it can become a matter of life or death. Eyewitness lineups require a witness to choose a suspect from a line of potential predators. Despite the proven errors and inaccuracies in the process, this form of evidence continues to have an impact in criminal trials across the country.

How do eyewitness lineups work?

According to the Innocence Project, eyewitness lineups should contain several people who match the description of the perpetrator. The lineup administrator leads the witness through the process, as they determine whether the suspect is present in the lineup. Yet, in some cases, there is only one person that has the same characteristics of the perpetrator.

Furthermore, the lineup administrator may lead the witness through physical and verbal cues to choose a certain person from the lineup. It is also critical to know that the suspect may or may not be present in the lineup.

Where does human memory come in?

There are several factors that influence a person’s memory of an event or details of a person’s appearance, as reported by PBS.org. This includes the following:

  • Whether a weapon is present during the crime
  • Whether the perpetrator is a different race than the witness
  • Amount of lighting present at the crime scene
  • Distance the witness was standing from the actual crime
  • Amount of time that has passed from when the crime occured to the time of the lineup

After the crime occurs, people fill in memory gaps with implied facts, or details that may have not actually happened. As time goes on, instances that may have seemed fuzzy, become solidified with details that may be untrue.

In addition, when people are under tremendous amounts of stress or trauma, they may not be able to recall critical details regarding the crime. All of these factors can prompt a witness to choose an innocent person from an eyewitness lineup. This in turn could lead to the wrongful conviction of an innocent person.