Pennsylvania eyewitness testimony: It’s not as reliable as it seems

Frequently, law enforcement agencies throughout Pennsylvania gather eyewitness statements to use as evidence in criminal investigations. This type of testimony has historically been considered among the most reliable sources of proof. However, research shows that eyewitness testimony may not be as reliable as it seems.

Eyewitnesses commonly misidentify people or misremember events. As a result, many people have been falsely convicted of crimes, such as robbery, sexual assault and murder. According to the Innocence Project, misidentifications by eyewitnesses contributed to over 70 percent of the convictions that were overturned based on DNA evidence.

Why is eyewitness testimony unreliable?

The human mind does not generally work like a video recorder. Consequently, a person cannot rewind and replay a series of events in their mind exactly as they occurred. Instead, there is a level of subjectivity in the way that people recall events they witnessed and things they saw. As such, a number of factors may contribute to the inaccuracy of eyewitness testimony and conflicting witness statements. Generally, these factors can be separated into two categories - estimator variables and system variables.

Estimator variables

According to the American Bar Association, estimator variables are those factors that are outside the control of the criminal justice system. These variables may impact how an eyewitness perceives events, as well as how he or she recalls them. Some of the factors that may fit into this category include the following:

  • The witness' age
  • The amount of time the witness had to see the perpetrator
  • Whether the race of the witness differs from that of the perpetrator
  • How far away the witness was from the perpetrator of the crime
  • The lighting in the area where the crime occurred
  • The witness' level of intoxication

Other factors, such as the personal characteristics of the perpetrator, can also effect witness identification. Changing things, including a person's hairstyle, hair color, facial hair or hat, may alter how a witness perceives him or her. High stress situations can also impact witness recall and identification. This is especially true in situations involving a witness. In these cases, witnesses often put most of their attention on the weapon rather than on the person who is holding it.

System variables

System variables are those factors that can be controlled by the criminal justice system, according to the Innocence Project. Typically, these factors include the methods used by authorities to withdraw information from witnesses' memory. In some cases, law enforcement may be in a hurry to solve a crime and get a conviction. As such, they may not emphasize certain steps, which are aimed at minimizing eyewitness errors.

Identification procedures, such as lineups and photo arrays, are among the main types of system variables that can affect the reliability of eyewitnesses. For example, using photos with differing lighting, or photos of different sizes, may make one suspect stand out to a witness over the others pictured. Additionally, witnesses often feel like they have to pick a suspect out of a line up, unless law enforcement officers stress that the suspected perpetrator may not be included.

Seeking legal counsel

Eyewitness testimony in Pennsylvania can easily be tainted, especially if law enforcement does not follow the proper protocols. This may lead to people being convicted of crimes they did not actually commit. In order to avoid a wrongful conviction, it may be of benefit for people charged with criminal offenses to obtain legal representation. An attorney may help them to form a thorough criminal defense, which may include questioning the accuracy of eyewitness testimony.