Wednesday, August 27, 2008

Visual Recognition...But I wasn't wearing my glasses

Image courtesy of The Innocence Project.

The Innocence Project recently posted the story of Darrell Edwards who was convicted of a New Jersey murder of a store owner based, in part, on testimony from an eyewitness who claimed that she saw him from 271 feet away in the dark when she was not wearing her prescription glasses. Full story here. The Innocence Project is currently working on overturning Mr. Edward's conviction based in part on DNA evidence recovered from a gun and sweatshirt found at the scene that did not match Mr. Edwards as well as challenging the eyewitness identification from that distance. As part of the challenge, the Innocence Project cites the results of a 2004 study by expert Geoffrey Loftus and Erin M. Harley:
In its motion seeking a new trial, the Innocence Project cited a scientific study by Geoffrey Loftus of the University of Washington and Erin M. Harley of the University of California, Los Angeles, two national experts in the field of visual cognition and eyewitness memory. Their 2004 study “Why is it easier to identify someone close than far away?” shows how the human visual system becomes more and more unable to perceive and identify facial details as the face they are looking at moves further away – even if they know the person they are trying to identify.

The study consisted of experiments designed to test the hypothesis that the visual system is unable to “perceive and encode progressively coarser-grained facial details as the face moves further away.” The study used a mathematical model to ensure that the same special proportions in a close image were replicated at distances. The study found that after 25 feet, face perception diminishes. At about 150 feet, accurate face identification for people with normal vision drops to zero.

The motion also cites a 2008 article in the journal, Law and Human Behavior by Gary Wells and Deah Quinliven at Iowa State University in which they describe experiments into how people suffer from “hindsight illusion” that leads them to believe they could see a face better than they actually did, once they are told it was someone they know.

Remember to ask the question that led Cousin Vinnie to remark, "Maybe its time for a thicker pair of glasses, Dear."

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