With the rise of DNA evidence, we now know more than ever about how often eyewitnesses make mistakes. It’s staggering. A lot of people go to jail because a confident eyewitness makes a mistake in court and picks out the wrong person.

Why does this happen? While every case is unique, here are three common reasons:

1. The witness did not have optimal viewing conditions

Perhaps the lighting wasn’t good or maybe the witness was too far away from the scene of the crime to make an accurate assessment. Perhaps the crime happened so fast that they just didn’t have time to watch carefully.

2. The witness got distracted

Bright lights and loud noises are common distractions, such as one might see in a hit-and-run accident. In weapon-related crimes, the weapon itself can distract the witness, who pays more attention to the gun or knife than the person.

3. The witness had a distracting internal state

For instance, perhaps the witness is prejudiced against people of a certain ethnicity or perhaps the witness just wasn’t paying attention when the event took place. The way that the person feels and thinks during the crime can often change what they see and how they analyze it later.

Of course, just knowing why people make these mistakes is not enough. What we need to do is find a way to combat these mistakes and keep innocent people out of jail.

With as common as this problem is, those who face criminal accusations need to know all of their legal rights and options. It could make all the difference between a wrongful conviction and an accurate end to the case.