The Biggest Cause of Wrongful Convictions
In a criminal trial, some of the most powerful and persuasive testimony can come from supposed eyewitnesses who can identify the accused or testify regarding the events underlying the offence. However, flawed, unreliable, and mistaken eyewitness testimony can have devastating consequences, and eyewitness misidentification has long been regarded as the leading cause of wrongful convictions. As Mr. Justice David Doherty of the Ontario Court of Appeals once wrote:
“The spectre of erroneous convictions based on honest and convincing but mistaken eyewitness identification haunts the criminal law.”
Scientific studies almost unanimously conclude that eyewitness testimony is unreliable due to the inability of the human mind to capture and preserve memories in the same way a camera does. Several factors affect an eyewitness’s ability to recall information, including:
- The passage of time – Memory decay occurs quickly. Even in the few hours between when an eyewitness sees an alleged crime and views a line-up or photo array of potential suspects, evidence of unreliability of the memory can be demonstrated. New information or experiences the eyewitness obtains even in this short period of time can influence his memory of the incident.
- Stress – Stress and anxiety impact an eyewitness’s perception of the alleged crime as well as his ability to recall the event later. In crimes involving weapons, stress levels are heightened, making memory even more unreliable.
- Distractions – Other activity occurring in the vicinity of the alleged crime can distract an eyewitness and affect his ability to recall what he observed with accuracy.
Credibility Can Be Attacked and Reliability Can Be Questioned
Aggressive defence counsel know the right questions to ask and facts to bring out to put doubt in the judge or jury’s mind about the reliability of eyewitness testimony. Questions that highlight an eyewitness’s vision or hearing limitations or incapacity due to intoxication or drug use get to the heart of the eyewitness’s ability to perceive the alleged crime. Evidence of poor lighting or a long distance between the eyewitness and the crime scene also raises questions about the accuracy of the eyewitness’s testimony. Additionally, evidence demonstrating assumption or bias on the part of the eyewitness, based on race or a preconception, can play a key role in challenging eyewitness credibility.
Furthermore, skilled defence counsel can and should make references in their submissions to juries to the growing number of wrongful convictions. Trial judges can instruct jurors about the need for them to be cautious in dealing with eyewitness testimony and discuss the inherent frailties of eyewitness identification due to the unreliability of human observation and recollection like that discussed above.
Additionally, zealous defence counsel can challenge eyewitness testimony by:
- Using opening statements and closing arguments to educate the jury on scientific findings about memory
- Making a motion to exclude eyewitness testimony due to credibility questions
- Using cross-examination to demonstrate to the jury that an eyewitness’s testimony is unreliable
- Using experts to educate the jury about the science behind memory and research on memory reliability
All evidence used by Crown Prosecutors can and should be vigorously challenged by defence counsel. This is even more vital when the evidence is based on something as unreliable and fallible as human memory.
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