Study reveals why it is so difficult for an eyewitness to positively identify criminals

A study has investigated the accuracy of eyewitness identification.

Eyewitness identification can sometimes be the difference between whether someone goes to prison or not and given its importance, a study has tested what factors could impact whether an eyewitness makes a correct identification or not.

Titled The masked villain: the effects of facial masking, distance, lighting, and eyewitness age on eyewitness identification accuracy, the study saw 1,325 participants look at a group of real people and then try to identify them in a series of 'live targets' - an 'eight-person simultaneous photograph line-up'.

Participants were given 20 seconds to look at the people before they tried to identify them in the line up.

However, the variables of the study included the distance the people were from the participants, how they were lit and whether they wore anything which concealed part of their face.

Pexels/ Ron Lach

Some of the live targets wore sunglasses and hoods, while the distances between the eyewitnesses and live targets ranged from five metres, to 12.5 metres and 20 metres.

NYU Shanghai Assistant Professor of Practice in Psychology and leader of the study Thomas Nyman said, as per NYU Shanghai: "A lot of [the design] had to do with what are real-life settings like. What do criminals actually do? If it’s worse lighting you might think now is an optimal time to go out and commit a crime, because no one is going to see you."

The study also took into consideration how old the eyewitnesses were - aged between five years old and 90.

Pexels/ Anna Shvet

The study found the accuracy of a positive identification with no facial masking at five meters was 69 percent - 96 percent for 'only 18-44-year-old' participants - but 17 percent at 20 meters.

In light conditions when the person wore sunglasses and placed five meters away, participants' identification accuracy was 32 percent and an even lower 20 percent at 20 meters.

The study resolved: "In the present study we found that increased distance, decreased lighting, and facial masking (internal and external) had a substantially negative impact on identification accuracy and discriminability.

"Importantly, the negative impact of facial masking was more pronounced under optimal (vs suboptimal) viewing conditions with internal (vs. external) facial masking being most detrimental to identification accuracy and discriminability.

"We recommend that law enforcement agencies and researchers report these variables to allow for the post-diction of the likely accuracy of an eyewitness decision."

Pexels/ Cottonbro studio

Nyman resolved: "The whole point of this [project] is to protect innocent people. We have clear information from the Innocence Project in the US and other cases around the globe, that of the people who have been convicted and later found to be innocent, approximately 70 percent have been imprisoned, at least partly, due to misidentification.

"[...] If you can exclude unreliable identifications, it would mean that fewer innocent people will go to prison. And that’s what this whole project is about: trying to protect people."