In courtrooms, on therapists’ couches and across the kitchen table, we count on the trustworthiness of our memories. But brain scientists are increasingly demonstrating that our recollections don’t exactly deserve the faith we put in them. They can be self-servingly Photoshopped, nudged off the mark by suggestion, and corrupted by being dragged out and rehashed.
Just how flimsy are the foundations of memory? So flimsy that in a neuroscience lab at the Massachusetts Institute of Technology, researchers were able to fabricate fearful memories and implant them in the brains of mice using a few electrical probes, some photo-sensitive chemicals and a miniature flashlight.
For the mice, the false memory — of a painful shock delivered in a specific place in their maze — was more than a momentary fright: the creatures’ certainty that the memory was real could be gleaned by their behavior. As all bad memories are meant to do, this one taught the mice to avoid the spot in which they “recalled” getting a painful jolt.
“Memories can be unreliable,” the researchers noted in their study, published in today’s journal Science.
The researchers, led by Susumu Tonegawa of MIT’s Picower Institute for Learning and Memory and the RIKEN Brain Science Institute outside of Tokyo, suggested that some false memories may have origins in real experience but are then transformed beyond recognition.
When an original memory is brought to mind in the midst of new and different emotional circumstances, that memory may take on new and different emotional colors. A happy memory can turn dreadful if recalled in the moments before a car accident, or a frightening memory is defanged when revisited in the safety of a therapist’s office.
The latest research underscores that reliance on the memory of witnesses can be a poor guide to the truth in criminal cases, experts said. But it may also help pave the way to new treatments for such conditions as post-traumatic stress disorder.