Many people believe that eyewitness testimony provides the most compelling evidence in a court of law. While this holds true in some cases, in other situations the words of a witness to an alleged crime can seem weak under cross-examination, especially in connection with conflicting physical evidence.
The fallibility of an eyewitness depends upon many factors.
A review of overturned convictions
According to the Association for Psychological Science, a review of court cases overturned due to advances in forensic sciences revealed weaknesses in eyewitness testimony. Some of these cases resulted in innocent people serving many years of prison time. The testimony sometimes falsely identified the perpetrator of a crime and often involved cross-racial misidentifications.
In many of these overturned cases, DNA testing provided new evidence that became admissible in court after the development of better methods. This high level of accuracy effectively countered the statements of witnesses.
A look at the malleability of memory
Testable conditions show that memory becomes vulnerable to different levels of distortion, often without the awareness of the witness. Evidence shows that memory varies from person to person and from situation to situation, sometimes providing a high level of accuracy and sometimes coming up with fictional beliefs.
Unconscious memory distortions and biases exist among even the most “reliable” witnesses. The sincerity of the witness might mean that he or she believes their testimony, but it does not ensure the accuracy of the memory. In a jury trial, jurors might believe that the intensity of a crime situation might lead to better memories, but research shows this does not necessarily hold true to form. The reliability of an eyewitness has limitations.