Eyewitness memory is reliable, but the criminal justice system is not

The reliability of any type of forensic evidence (e.g., forensic DNA) is assessed by testing its information value when it is not contaminated and is properly tested. Assessing the reliability of forensic memory evidence should be no exception to that rule. Unfortunately, testing a witness’s memory irretrievably contaminates it. Thus, only the first (properly conducted) test is relevant to the question of whether eyewitness memory is reliable. With few exceptions, the results of studies conducted in the lab and in the real world show that confidence is highly predictive of accuracy on the first test, and high-confidence often implies high accuracy. The fact that many eyewitnesses are known to have made high-confidence misidentifications in the courtroom has cemented the almost universal impression that eyewitness memory is unreliable. However, it is the criminal justice system that is guilty of unwittingly using contaminated memory evidence (relying on the last memory test, in court) in conjunction with an improper testing procedure (namely, a courtroom showup) to win convictions of the innocent. That mistake should no longer be blamed on the unreliability of eyewitness memory.