Many people consider eyewitness testimony to be a powerful form of evidence. However, eyewitness accounts are not always accurate. They are also subject to influence by various factors.
Understanding the reasons behind these inaccuracies helps ensure fair outcomes in investigations and trials.
Memory distortion and reconstruction
A key reason why eyewitness accounts may be unreliable is due to memory distortion and reconstruction. Memory is not like a videotape that records events. Instead, it is malleable and subject to influence. Factors such as stress, anxiety and the passage of time can distort memories. This can lead people to misremember or fill in gaps with false information.
Suggestive questioning and lineup biases
Another factor affecting the accuracy of eyewitness accounts is suggestive questioning and lineup biases. Law enforcement officers or prosecutors may influence witnesses by asking leading questions or providing cues that suggest certain details. Lineup procedures can also cause problems. They may lead witnesses to incorrectly identify suspects based on subtle cues or lineup composition.
External influences and expectations
External influences and expectations can also impact the accuracy of eyewitness accounts. Media coverage or prior knowledge about a case can influence how witnesses perceive events. They can also impact how a witness remembers details. People may also be more likely to identify a suspect who matches a stereotype or preconceived notion, even if that identification is inaccurate.
Corroborating evidence and expert testimony
Given the limitations of eyewitness accounts, it is important to rely on evidence and expert testimony. Both can help corroborate or challenge eyewitness testimony. Physical evidence, surveillance footage and forensic analysis can provide valuable context and verification of events. Expert witnesses can also offer insights into the reliability of eyewitness testimony.
Per Psychology Today, a study of 349 convictions overturned by DNA evidence revealed that eyewitness misidentifications contributed to 70% of those convictions. This statistic highlights the impact eyewitness misidentifications have on the criminal justice system and the importance of implementing measures to mitigate such errors.