We come to the truth in many ways. We read books, think, listen to other people and experience things directly. Other people lie sometimes. They skip the important details. Our thoughts are sometimes mangled. The most convincing way to learn things is to experience them ourselves. Our memories seem to be our unmediated store of the truth: the things we know for certain happened. But other people can give us memories of things we never experienced.
Elizabeth Loftus and colleagues conducted one of the earliest experiments showing how to do this, and highlighting how dangerous it is to rely on what we remember. They showed volunteers a clip of a road accident. Afterwards, they asked some of the participants, ‘About how fast were the cars going when they smashed into each other?’ They asked others how fast they were going when they collided, bumped, contacted, or hit. Participants who heard the question with the verb smashed estimated that the cars were going faster*.
A week later, the experimenters contacted the participants again and asked them further questions on what they remembered about the accident. In particular, was there any broken glass at the scene? Those who’d been asked how fast the cars were going when they smashed were more than twice as likely to wrongly remember seeing broken glass after the accident. A single, apparently innocuous word changed what people remembered, and their memories afterwards built all the details of the accident to be consistent.
This was an early experiment. Researchers have since become bolder and better at manipulating people’s memories. They’ve had participants remember robbers carrying a screwdriver that wasn’t there. In controversial experiments, they’ve implanted memories of childhood events that never happened including being lost in a shopping centre, taking a flight in a hot air balloon and even meeting Bugs Bunny (a Warner Brothers character) on a trip to Disneyland.
When The X-Files was popular, the number of reported alien abductions, some recovered under hypnosis or in therapy, rose dramatically. It seemed like a fad, but the unfortunate abductees were just as distressed when talking about their memories as people who really had traumatic experiences. Memory’s a strange thing, and just as unreliable as those grainy photos of UFOs. The truth may be out there, but don’t rely on finding it in your head.
Chris Paley holds a PhD from the University of Cambridge, and is the author of Unthink, which has been published in six languages.
*The verb contacted elicited the lowest estimates of speed. Worth remembering if you’re ever responsible for a smash.
Other references in Unthink