How your brain invents memories
Changing one word in a question can make people remember broken glass that was never there.
▶ Start the storyWe tend to think of memory as a recording: press play and the past comes back. It doesn't work that way. Memory is rebuilt each time you recall it, and the rebuilding can go wrong. A false memory is when you remember something that never happened, or remember it differently from how it happened.
In a famous 1974 study, Elizabeth Loftus and John Palmer showed people videos of car crashes, then asked how fast the cars were going when they smashed into each other. Other people got the same question with a milder verb, like hit or contacted. The verb predicted people's speed estimates better than the actual speed did. In a follow-up, more people who heard smashed later said they had seen broken glass. There was no broken glass in the video.
Step 1: Watch
People watch a video of a car accident.
Step 2: Ask
How fast were the cars going when they smashed, or hit, or contacted each other?
Step 3: Estimate
The verb predicts the speed people report better than the real speed does.
Step 4: Remember
More people in the smashed group later recall broken glass that was never in the video.
It goes further than details. The lost in the mall technique started as a student's extra-credit assignment: Jim Coan, one of Loftus's students, gave his brother a short story about getting lost in a shopping mall at around age five. It had never happened, yet his brother added details of his own. In a formal follow-up study, about a quarter of participants came to remember that invented childhood event.
Why would a brain do this? Your memories of personal events get rebuilt using your general knowledge and expectations, and suggestions or misleading information can blend in. True and false memories also rely on overlapping brain systems, which is why false ones can feel completely real.
The lesson is humbling. Feeling sure about a memory is not proof that it happened.
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Recap
Memory is rebuilt every time you recall it, so feeling sure is not the same as being right.
Surprising fact · Hearing smashed instead of hit made more people remember broken glass that was never in the video.
Sources (5)
No source, no claim. Every fact in this lesson (26 claims) cites at least one of these.