You probably realize that memory doesn’t work exactly like a video recording. If it did, then you wouldn’t forget where you put your car keys or the name of the person you met at a party last week. You could simply think about the past and magically recall everything in great accuracy. Even so, you may not realize the extent to which your memory of events, people, places, and experiences can be inaccurate. Memory is reconstructed, not recorded, so there are bound to be inaccuracies.

The fallibility of memory can be seen most clearly in criminal eyewitness testimony, which can be highly unreliable, so much so that it should not be used as the linchpin of a criminal case. There have been several highly publicized cases in which eyewitness testimony helped to put a suspect, later found innocent, behind bars. The witness may be positive that she has made a correct identification; however, certainty means little. No matter how certain the witness may be, she could be completely wrong.

Why do we often remember events differently from the way they occurred? There are several factors that can affect our recall:

• Stress
  In a stressful situation, we may miss important information in our environment. This helps to explain why a victim of crime may not accurately remember details of her assailant. If a weapon is pointed at the victim, she is most likely focusing on the weapon and not at the assailant, whose face she may be asked to describe later.
• Passage of Time
  The passage of time can also affect memories, causing them to get distorted or hazy. Research has shown that people may even confuse facts or remember details that never occurred.
• Power of Suggestion
  Human memory is highly influenced by suggestion. For example, a crime victim studying a police line-up may be influenced by the bias of the police investigators, who, through the power of suggestion, lead the victim to select the police’s prime suspect.

If memory isn’t accurate, can we ever fully trust our recall of events? Probably not. How do we know that we haven’t recalled something differently from the way it happened? Well, there’s no way to know for certain. It’s important to realize that no matter how sure we are of the accuracy of our memory, we are probably recalling the past through a filter.

The topic of human memory and recall is a broad topic that cannot be covered thoroughly in a single blog post. Here are a couple of articles on memory as it relates to eyewitness testimony:

Eyewitness Testimony in an Imperfect World (The Washington Post)

Reevaluating Lineups: Why Witnesses Make Mistakes and How to Reduce the Chance of a Misidentification (The Innocence Project)