Can Unreliable Eyewitness Testimony Convict an Innocent Person?

 Posted on March 13, 2025 in Criminal Defense

While eyewitnesses to a criminal offense can provide compelling testimony, the average person’s memory of a specific event is susceptible to many biases and errors. Unfortunately, jurors love eyewitness testimony and are much more likely to convict a defendant when another person witnesses the crime. Witnesses to a crime or accident are commonly interviewed by law enforcement after making a "positive" ID, then by lawyers from both sides, perhaps in a deposition, and finally in court in front of jurors and the judge.  

While eyewitness testimony may well be the most persuasive form of evidence presented in court, its accuracy may be seriously flawed. Alarmingly, faulty eyewitness testimony has been implicated in at least 75 percent of DNA exoneration cases – more than any other cause. Speaking to an experienced Chicago, IL criminal defense attorney about potential eyewitness testimony can be crucial to the outcome of your trial.

Can Memories Be "Introduced" to a Witness Through Leading Questions?

Between the time a witness sees an event and reports it, memories can be scrambled by exposure to false information. In one study on the accuracy of eyewitness memory, college students watched a video depicting a small red car hitting a pedestrian at an intersection with a stop sign. Some of the students were then asked "leading" questions, such as "How fast was the car driving when it passed the yield sign?"

Questions like these were designed to be misleading, yet when the students were shown an original still of the car passing the stop sign and another still of the car passing a yield sign, those who had been given false information about the yield sign picked the false photo as what they originally saw. Misinformation fed to the students in the form of a leading question led to false memories.

This means that any type of leading question by law enforcement and lawyers can contaminate a witness’s memory of the incident. This misinformation phenomenon leads people in studies to incorrectly remember not only small but crucial details of a perpetrator’s appearance but even an object as large as a barn that was not actually there.

While young adults are susceptible to leading questions and misinformation, the elderly and children are even more susceptible. Even when there is no deliberate intent to deceive, misinformation occurs easily. The slightest difference in the wording of a question can cause false memories.

As an example, subjects in a different study were significantly more likely to answer "yes" when asked, "Did you see the broken taillight?" than when asked, "Did you see a broken taillight?" Even when unintentional, the word "the" implies that there definitively was a broken taillight, making the witness less likely to contradict the statement.

What About Situations Where There Are Several Eyewitnesses?

When police question eyewitnesses to an auto accident, it can be exasperating for one witness to say the car that left the scene was a black sedan, the next person claims it was a blue compact car, and the next person believes it was a dark brown SUV. Witnesses to an accident or crime tend to talk to one another immediately following the incident, contaminating their memories of the event.

In another study, researchers paired individuals to watch a video together. Because each subject wore differently polarized glasses, even though they watched the same video, they saw two different versions. The two versions differed in more than eight details. After watching the video, the two "witnesses" worked together on a dozen memory test questions and then answered another 20 questions individually.

The accuracy regarding the questions the two had not discussed was about 79 percent. However, when questioned about the items the two had discussed, their individual responses were only about 34 percent accurate, meaning witnesses allow other witnesses to alter their memories of what they saw.   

Overall, human memory is susceptible to a broad array of errors and biases. People can forget parts or all of the events that occurred and can routinely mix up details. Humans can even remember complex events that never happened. Once these errors occur, they can be difficult to unravel.

Contact a Cook County, IL Criminal Defense Lawyer

If you are on trial for your life and your future, a misidentification by an eyewitness can be devastating. Speaking to a Chicago, IL criminal defense attorney from Luisi Legal Group will help ensure this does not happen to you. Attorney Luisi is a highly skilled litigator who is in Chicago criminal courts on a daily basis. Call 773-276-5541 to schedule your free consultation.