Can You Trust Eyewitness Testimony?

Eyewitness reports play a key role in crime fiction, especially legal fiction. Two guys say the other guy did it, and our intrepid sleuth has to figure out which one is telling the truth. Fortunately, after a fair amount of detecting, he or she is able to find a witness to the crime, and the case is solved--until the witness refuses to testify, of course. Or suffers an untimely death at the hands of the killer.

In any case, the importance of eyewitnesses, and their memory, is undeniable in our stories. That's because of how important it is in real life. Often, the only evidence a detective has to go on at first are eyewitness reports. In trials, eyewitness testimony is seen as the "smoking gun" by many juries.

But how reliable is our own memory?

As it turns out, not very.

We sometimes think of memory like we're playing back the video tape of what we experienced. In truth, researchers say, we rebuild our memories each time we recall them, more like a box of Legos than a recording. In fact, it's more accurate to say that we don't remember events--we remember the last time we remembered them. And each time, we have to build them "from scratch, and if much time has passed you stand a good chance of getting the details wrong. With a little influence, you might get big ones wrong."

This leads to something called the misinformation effect. With a little bit of prodding and poking, researchers can get people not only to misremember things that actually happened, they can easily implant new memories like getting lost at a shopping mall or shaking hands with Bugs Bunny at Disney World (Bugs Bunny is a Warner Bros. character and wouldn't be found at a Disney park).

Elizabeth Loftus summarizes what we know about memory by saying: "If there were three words that I would come up with to to describe what memory is, I would say memory is suggestive, subjective, and malleable."

Remember that the next time you listen to eyewitness testimony. Or when you remember anything.

Or think you remember.

Recommended Reading
Slate series on manipulating memory
YouAreNotSoSmart: Misinformation Effect