An analysis of the first 239 DNA exoneration cases by the Innocence Project identified several common causes of wrongful convictions. Eyewitness misidentification was the most frequent factor, contributing to about 75% of cases. Other significant causes included flawed forensic science (about 49%), false confessions (about 23%), and unreliable informant testimony (about 18%).

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Despite the known fragility of human memory, the legal system, including police, prosecutors, and courts, often depends heavily on eyewitness testimony for criminal prosecutions. This reliance is problematic because memory is a reconstructive process, making eyewitness accounts susceptible to errors that can lead to faulty identifications and, ultimately, wrongful convictions.

Eyewitness Testimony and its Unreliability

The Innocence Project is a non-profit organization dedicated to exonerating individuals who have been wrongly convicted of crimes. A significant focus of its work is on cases where convictions were based on flawed eyewitness testimony.

The Innocence Project

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

When eyewitnesses receive confirmatory feedback after giving their testimony, their confidence in their understanding and recall of the events is increased. This is a problem because jurors make decisions based on the confident of witnesses, which can be overinflated due to confirmatory feedback regardless of the actual validity.

Post-identification feedback effect

An interview procedure developed by cognitive psychologists based on memory retrieval research and understanding. Allows the witness to talk with little to no interruptions. Uses techniques to try to simulate putting the witness back to the scene of the crime in order to recreate the events.

Cognitive Interview

Information presented after someone witnesses an event that is misleading and can potentially change their memory of that event. It is often problematic in criminal cases when witnesses are given MPI.

Misleading Postevent Information (MPI)

People tend to pay attention to the weapon while a crime is being committed (a highly emotional situation). This can restrict a witness' awarenesses of the events leading up to and during a crime.

Weapons focus

Eye-witness testimonies are likely to be flawed or unreliable if the witness is exposed to an inaccurate account of the crime, particularly if this account comes from another person in a social context. While discussing the crime with co-witnesses may help to improve one’s overall memory of the event, inaccurate information encountered during such an interaction is likely to lead to memory distortions.

The impact of socially encountered misinformation on eye-witness testimonies 

Though human memory is fragile, legal and investigative processes often depend on eyewitness testimony. This reliance is risky, as suggestive police identification procedures can cause eyewitnesses to make incorrect identifications, and such false testimonies can result in wrongful convictions. According to the Innocence Project's analysis of the first 239 DNA exonerations, eyewitness misidentification was a contributing factor in approximately 75% of these cases, establishing it as the leading cause.

Eyewitness Misidentification

Suggestibility is a memory distortion error where individuals accept and incorporate misinformation from external sources into their personal recollections. This process, which can be triggered by leading questions from sources like a therapist or a police interviewer, can lead to the creation of false memories for events or details that were only suggested, not actually experienced.

Suggestibility

Common Causes of Wrongful Conviction in DNA Exoneration Cases

The investigation into Elizabeth Smart's abduction illustrates the benefits of careful eyewitness management. The sole eyewitness, her nine-year-old sister Mary Katherine, was handled with caution by the FBI and police. To avoid implanting false memories or misleading her, they refrained from using standard procedures like police line-ups or pushing for a composite sketch. This preservation of her memory proved crucial when, months later, she recalled the abductor's voice from a prior encounter, leading to his identification and Elizabeth's safe return.

The Elizabeth Smart Case: An Example of Cautious Eyewitness Procedures

Within the legal system, judges can implement safeguards to address the potential unreliability of eyewitness testimony. These measures include instructing the jury about the possibility of misidentification and having the authority to suppress testimony that is deemed untrustworthy.

Judicial Safeguards for Eyewitness Testimony

From a psychological perspective, analyze why this eyewitness's testimony might be unreliable, despite their high level of confidence. Explain the underlying principles of memory that support your analysis.

Evaluating an Eyewitness Account

Ronald Cotton's story illustrates that wrongful convictions based on eyewitness testimony are not unique. There are instances where individuals have been falsely convicted and placed on death row before being later exonerated.

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