For three years, Rita Magil relived the scene in her nightmares and in daytime flashbacks.
“I could see two cement pillars that my car was being propelled towards,” she says. “I remember going towards them, being unable to stop the car, powerless and totally out of control, and watching my death coming.”
In July, 2002, Ms. Magil was cruising down Sherbrooke Street in Montreal when another vehicle smashed into her white Fiero, pushing it over the sidewalk toward the pillars that mark the front entrance of the Imperial West apartments, near Kensington Avenue.
In the months and years that followed, the memory left her stressed and shaken when it surfaced, unbidden, day and night.
As her physical wounds healed, the occupational therapist tried to get on with life. She bought another car, forced herself to drive by the intersection where the accident happened and tried not to be overly cautious behind the wheel. But the crash continued to haunt her.
Then, last year, she saw a newspaper ad seeking volunteers for an experiment on post-traumatic stress syndrome.
The experiment, run by McGill University researcher Alain Brunet at the Douglas Hospital, aimed to replicate a revolutionary finding made in animal studies — that memories of traumatic events can be altered with the use of drugs.
The idea is controversial, because our memories make us who we are. Ethicists worry that one day criminals will be able to pop a pill and remove the shame or guilt from their memories, or even the details of a murder or rape. There is concern that dictators might be able to create drones, with no memories of their pasts.
We have come to accept the notion that we can tinker with mood or personality through pharmaceuticals, and we know that drugs such as alcohol can wipe out the memory of a bender. But the notion of deliberately altering a specific memory seems more disturbing.
Dr. Brunet and his colleagues stress that they aren't trying to erase or even edit traumatic memories. They want to dampen their emotional component, so people will be able to recall what happened without constantly reliving the associated panic, humiliation or pain.
Their theory is that the emotional memory of an incident — what Ms. Magil was feeling as she faced death — is stored in a different part of the brain than the details of flying over the curb toward the pillars, wiggling her toes to see if she was paralyzed, hearing the other driver shrieking, “Is she dead, is she dead?”
Dr. Brunet knew the experiment was a long shot. It is one thing to give rats a drug that makes them forget they have been given an electric shock. It's quite another to pharmaceutically tamper with human subjects' long-term recall.
“We were skeptical when we began,” he says.
People remember emotional events, whether terrifying or joyful, more vividly than everyday experiences. Your wedding day will stand out more than the dinner you ate in front of the television a few years into your marriage.
It seems that the stress hormones the body produces during emotionally charged events help imprint memories in a particularly powerful way.
Think about it from an evolutionary perspective: If you retain a strong memory of the terror of being bitten by a snake, you are more likely to take evasive action the next time you see something slithering through the grass.
Even hearing about a traumatic event seems to improve memory. In California, researchers James McGaugh and Larry Cahill showed one group of volunteers slides that were accompanied by a dramatic story about a boy being hit by a car and nearly losing his leg. A second group saw the same images, but were told a less sensational tale.
The group that heard the more gripping narrative were better at remembering the details of the pictures they had been shown.
