Eyewitness testimony is often thought of as one of the backbones of the American justice system. When someone comes forward and says he or she saw the defendant at the scene of the crime, it’s hard not to imagine the jury gasping as they all realize that person must be guilty.
Often, that’s very far from the case. DNA testing has changed criminal cases forever, and one of the uncomfortable truths for those who place blind faith in the justice system is that DNA tests are constantly proving eyewitnesses wrong.
For example, some reports claim that eyewitness testimony gets contradicted in a stunning 70 percent of cases that get overturned by DNA evidence. These are cases where eyewitness helped make a conviction. A person was not just accused of a crime, but sentenced to jail. That person may have spent years behind bars. Then DNA evidence showed that the person’s innocence, which he or she had likely been proclaiming all along, held merit. That person didn’t do anything wrong. Someone else got off free while another went to jail.
Moreover, those eyewitnesses were wrong. They probably sounded very convincing and may even have believed what they were saying on the stand, but they were wrong. The gut-wrenching feeling of disbelief by the defendant wasn’t just for show. That was 100 percent real.
So, why does this happen?
There are many reasons, but one of the biggest is that memories aren’t actually static. According to a researcher from the National Academies of Science, you don’t see something and then remember it that way forever, even though you may think you do. Instead, memories are malleable and can change significantly over time, especially if you have to think over them repeatedly — as witnesses often do, multiple times, during a case. The witness may think he or she is being honest, but the memory itself is dishonest.
Automatic responses to danger
For alleged violent crimes, like a bank robbery with a firearm, researchers also point out that people automatically focus on things that don’t necessarily help them during the case. For instance, when a person pulls out a gun and holds it up in the air, most eyes are glued to that gun. People glance at the person’s face, but they’re not staring at it and committing it to memory. That means the memory can feel murky, even if the person was just a few feet away.
Open to suggestion
Because witnesses have these murky memories that can change, this leaves them potentially open to suggestion. If they’re shown a potential suspect by investigators, for instance, they may feel like they “remember” that person being at the crime scene when they’re really just warping the original memory accidentally.
The inaccuracy of witness testimony, as proven many times by DNA evidence, is just one reason why it’s so critical for those accused of crimes to know all of their rights.