Reliability of eyewitness testimony put to the test: Witnesses affected by tiny changes in accused's looks

Eyewitness testimony that identifies criminals can be very unreliable when the accused person makes even slight modifications to their appearance, a new study has found. The research, conducted by Carleton University psychology professor Joanna Pozzulo, suggests that even natural hair growth between the time a crime takes place and the witnesses' identification of the accused can cause mistakes. "Appearance changes that are fairly easy to achieve (e.g. growing hair) are sufficient to allow a culprit to go unidentified, presenting a serious challenge to the criminal justice system and society," Prof. Pozzulo said in her paper, written with student Janet Balfour and published yesterday in the journal Legal and Criminological Psychology.

Prof. Pozzulo studied 239 adults and 177 children, showing them a video of a staged purse snatching. She later showed them "lineup" photographs, some of which included the perpetrator with varying lengths of hair. Children and adults had difficulty correctly identifying the assailant when his appearance was slightly different in the lineup photos. "When there is a change in appearance, identification accuracy dramatically decreases," Prof. Pozzulo said in an interview yesterday. "We're not talking about an extreme makeover. We're talking about someone who decides not to cut their hair for a few months." She noted that eyewitness evidence is a major factor in criminal trials, and has been relied on in many cases that generated wrongful convictions.

Toronto criminal lawyer Steven Skurka said yesterday that mistakes by witnesses are the "greatest source of miscarriage of justice" in Canada and the United States. Witnesses are usually "well-meaning people" who have no intention of perjuring themselves, he said, but they often get things wrong and it is dangerous for juries to rely on them.

Still, Prof. Pozzulo added, "witnesses do get it right a lot of the time as well," and that's why studies of witness behaviour, and the procedures used by police to collect eyewitness evidence, are crucial. Prof. Pozzulo's current research is looking at ways to improve procedures used to get testimony from children who witness crimes. One problem with children is they tend to report "false positives" by choosing an innocent party when they are shown lineup photographs that do not include the alleged perpetrator of a crime they witnessed

Report here



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