You commonly hear it, "That is the face I will never forget," but most likely you will forget.
Research shows memories can change over time and affect what you remember, especially during an intense situation.
"You can't guarantee what somebody else sees even if it is passing right in front of their eyes," says University of Arizona professor and visual expert Mary Peterson.
Professor Peterson says during traumatic events memory is impaired when under stress.
"When people are anxious they tend to move their eyes around a lot unless there is something that causes them to fix on it so I think this use of see is hard to square what is happening," she explained. "We are all in the same scene but we are not all seeing the same thing we are not all looking at the same thing."
Pima County Sheriff's Department Detective Robin Crehan says since eyewitnesses are not in the same place at the same time their memories may be different.
"One witness will have part of one part of the event, another witness another part of the event essentially what you are doing is talking with everybody that had any observation at all and then you begin to put the puzzle together with those recollections," she said.
Those recollections are something that are factors in determining if someone is innocent or not.
A spokesperson for the Arizona Justice Project says the organization receives about 350 new client requests every year and in the past six years, 16 of their clients have been exonerated.
Private investigator Randy Downer Jr. says it is common for people who witnessed the same scene to have perceived details very differently.
"I have interviewed thousands of people on car accidents and so it is common for me to take statements from witnesses and have two people explain the dynamics of the accident one way and the third person saw something entirely different the and yet they are all telling the truth," said Downer.
He says that is something called the witness focus effect.
"As you can imagine if you are in the bank and somebody has a gun and pointing it at the teller and you are standing off to the side you are watching that gun to make sure it doesn't get pointed at you rather than the face of the suspect," said Downer.
Although each eyewitness's focus can be on something different, Professor Peterson says memories are not permanent and can change over time. She says an eyewitness's memory can be challenged when they speak with other eyewitnesses because they question their own memory.
"They will quite often say things like I will never forget that face because it was so traumatic for me I saw that face but science shows us that there are sometimes mistaken that person whose face they are remembering couldn't even possibly have been in that scene," said Professor Peterson.
"Statistics have shown that the confidence level of the person you are talking to doesn't really matter sometimes. There is very little difference in the accuracy of the recollection the other thing is sometimes they make may be certain they saw a particular color associated. it may turn out that was not the color at all," said Downer.
Detective Crehan says to help limit eyewitness error PCSD creates a relaxed atmosphere for the eyewitness during lineups.
"We want them to be at ease and calm and explain to them that the individual we are trying to identify may or may not be in these photographs," said Crehan.
The department also produces a neutral setting by using DMV photos to create lineups that do not reflect any criminal activity like mug shots.
She says the department considers eyewitness recollection an important component in an investigation and every little bit helps paint a bigger picture of what actually happened.
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