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Eyes (and Minds) Deceive: Witness Unreliability Casts Doubt on Death Penalty Rulings

The views expressed are those of the author and are not necessarily those of Scientific American.

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Three members of the U.S. House of Representatives contacted the Georgia State Parole Board two days ago in a futile attempt to reopen a clemency hearing for Troy Davis, who was executed on the night of September 21 for the killing of a Georgia policeman. In their letter, they pointed out that the board had concluded its hearing without having a chance to hear Jennifer Dysart, a psychologist from the John Jay College of Criminal Justice in New York who is an expert on eyewitness testimony.

The ethics of retaining the death penalty is a decision made by state governments and the courts, but scientists like Dysart have ever more to say about the accuracy of those who witness the crimes that produce death sentences. Parole boards should listen carefully before making up their minds because of the apparent unreliability of these accounts.

The Innocence Project, a litigation and public policy organization affiliated with the Benjamin N. Cardozo School of Law at Yeshiva University in New York, has found that mis-identification by eyewitnesses played a role in three quarters of the 273 cases of mistaken conviction later exonerated by DNA evidence in the U.S. In the Davis case, several of the eyewitnesses recanted their testimony prior to his execution.

Social scientists, too, have critiqued the validity of procedures used in identifying suspects. On September 19, the same day that the parole board held its clemency hearing, a study by Dysart and colleagues found that witnesses make more accurate identification of suspects in a double-blind, sequential lineup—one in which each individual member is viewed separately and the law enforcement official does not know who the suspect is. Most lineups, including Davis’s, recapitulate the typical Law and Order episode in which all of the members stand side-by-side and the cop knows who the suspect is. In the study, Dysart found that nearly 42 percent of eyewitnesses made errors in the traditional lineup, compared to 31 percent in a sequential one.

In an affidavit prepared for the parole board, Dysart pointed out that after Davis’s arrest in 1989 (see pdf with affidavit, Dysart study and an Innocence Project letter), investigators staged a crime reenactment for eyewitnesses and used “suggestive identification techniques.” In 2008, the Georgia Peace Officer Standards and Training Council adopted an eyewitness identification training program and no longer endorses these practices, which, Dysart contends, contributed to Davis’s misidentification. The psychologist was planning to end her testimony by saying, “…given the significant problems with the eyewitness testimony in this case, there is a substantial danger that multiple witnesses rendered faulty identifications. As a result, the Board should give little weight to the eyewitness testimony introduced by the State.”

It is too late for Davis, but maybe not for others. In June, the New Jersey Supreme Court issued new rules for determining witness reliability before presenting testimony to jurors. And the U.S. Supreme Court has accepted a case that relates to eyewitness identification.  Bit by bit, the accumulation of scientific findings may be helping to ensure that the innocent are not wrongfully accused.


Source: Wikimedia Commons












Gary Stix About the Author: Gary Stix, a senior editor, commissions, writes, and edits features, news articles and Web blogs for SCIENTIFIC AMERICAN. His area of coverage is neuroscience. He also has frequently been the issue or section editor for special issues or reports on topics ranging from nanotechnology to obesity. He has worked for more than 20 years at SCIENTIFIC AMERICAN, following three years as a science journalist at IEEE Spectrum, the flagship publication for the Institute of Electrical and Electronics Engineers. He has an undergraduate degree in journalism from New York University. With his wife, Miriam Lacob, he wrote a general primer on technology called Who Gives a Gigabyte? Follow on Twitter @@gstix1.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Postulator 2:52 am 09/23/2011

    Yes, we know eyewitness testimony is notoriously fickle. We know lie detectors lie (and most of the world’s civilise jurisdictions steer clear of them). We know that forensic evidence often obscures as much as it reveals. We know that judges and juries have conscious and unconscious biases that potentially affect the rest of the defendant’s life.

    So what are legislatures doing to fix all of this? In most cases, doing their best to block appeal avenues when evidence comes to light that the person who spent the last 10 years in jail is actually innocent.

    Link to this
  2. 2. oldvic 6:44 am 09/23/2011

    I encourage research into witness reliability, and the work to raise the awareness of society about its limits.

    I’d applaud until my hands fell off the decision to abolish the death penalty. It’s illogical (if we deem life to be untouchable, how do we justify taking it in cold blood?) and it doesn’t allow for the possibility of error.

    The thought of an innocent killed by the judicial system is enough to make me sick. Let’s imagine ourselves in that situation…

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  3. 3. Pepperhicks 10:49 am 09/23/2011

    The law did not trump science in this case. The 7 individuals that recanted were acquaintances of the accused! Do you think that once they realized that their testimony could lead to this persons execution that they may have had a change of heart? Lets look at whats not in dispute:

    1. The casings found at the scene were matched to the very same gun Troy Davis used in a previous robbery.

    2. All the eye witnesses agree that he was the individual pistol whipping a homeless man over a beer that day.

    The guy was scumbag, and regardless of the constitutionality of the death penalty, deserved what he got. Stop trying to act like this was some poor innocent man caught up in horrible situation. This was by no means a travesty of justice. There are plenty of other folks on death row that deserve the attention of the media, this guy was not one of them.

    Using the inflammatory headline as a guide maybe we should let anyone out of prison that was convicted with the use of eye witness testimony to place them at the scene of a crime.

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