Human memory is notoriously unreliable, especially when it comes to details. Scientists have found that prompting an eyewitness to remember more can generate details that are outright false but that feel just as correct to the witness as actual memories.

In day-to-day life, this isn’t a bug; it’s a feature. We can’t possibly remember every tiny detail we see, but our memories would feel incomplete if there were big swaths of gray running through them. So the brain fills in the details as best it can, borrowing from other memories and the imagination in order to build what feels like a complete picture.