People are often tempted to trust eyewitness accounts almost unflinchingly. As soon as someone claims to have seen another person at a crime scene, they assume that paints a very precise picture of what actually happened there.
Science, however, tells the opposite story. It warns against trusting eyewitness accounts, as eyewitnesses are often rather blatantly wrong.
For instance, one man got a death sentence after an alleged murder. Five eyewitnesses played a role in that sentence. He went to jail, where he waited for nine years. That's when DNA testing cleared his name.
That's a hopeful story, in some ways, in that the man's life was spared. However, he still lost almost a decade behind bars, during which he feared he would be executed.
This is not uncommon. Researchers with the Innocence Project looked at 239 convictions that DNA evidence later helped to overturn. Stunningly, 73 percent of those cases involved eyewitness testimony. In about 33 percent of the cases, there were two or more eyewitnesses.
As you can see, people aren't just wrong occasionally. They're wrong a lot, and multiple people are often all wrong about the same set of facts. While DNA testing has helped to expose this, it still raises a lot of questions about all other convictions, especially in cases where there simply was not any DNA evidence to be used one way or the other.
It's important to know your rights when you are facing criminal accusations, as these cases show that the justice system is not always as good at getting to the bottom of things as many people believe.
Source: Scientific American, "Why Science Tells Us Not to Rely on Eyewitness Accounts," Hal Arkowitz and Scott O. Lilienfeld, accessed Jan. 22, 2018