Science Is Inching Closer to the Possibility of Erasing Bad Memories

What if we could selectively erase bad memories, whether of war, violence or just a bad relationship? Although scientists have been attempting to tinker with memory and its place in the mind since the late 1960s, it's only recently that science has really begun to hint that this might be possible after all, describes Virginia Hughes at National Geographic.

It all comes back to electroconvulsive therapy (ECT), the treatment infamously portrayed in One Flew Over the Cuckoo's Nest. Hughes explains the limited state of knowledge about this method:

Today ECT is used as a last resort for people with severe depression who do not respond to antidepressants, psychotherapy, or other treatments. It’s done in a hospital room, after the patient receives muscle relaxants and general anesthesia. A brief electric current passes through the brain, inducing a seizure. For reasons no one yet knows, it usually works: ECT had an 86 percent remission rate for people with major depression, according to one study.

To investigate whether and how ECT can banish bad memories, researchers showed study participants two disturbing slideshows. One slideshow depicted a woman being abducted at knife point, the other showed a kid being hit by a car and then having his body surgically put back together. The participants came back to the lab a week later, Hughes described, where they were shown the first slide from one of the stories to trigger their memories. After that, some received ECTs, and then all of them were quizzed about both of the slideshow stories.

The results, Hughes reports, were starkly contrasted between the two groups: 

Participants who did not undergo ECT got about half of the questions about the triggered memory correct, compared with 40 percent of questions about the other story (which they had not seen for a week).

In stark contrast, participants who received ECT seemed to have no memory of the story they had been reminded of — they scored a 25 percent on a four-answer multiple choice test, the same as guessing at random. The same participants showed significantly better recall — 35 percent — of the second, non-triggered story. ECT, in other words, selectively erased the memories that were being actively recalled.

How the ECT manages to do this, however, remains an open question in need of more research. Likewise, it'll take years to resolve the question of whether this technique should be used to help the traumatized or broken-hearted.

More from Smithsonian.com:

Memory Blocks 
What Scientists Know About Repairing Memories 

Rachel Nuwer | | READ MORE

Rachel Nuwer is a freelance science writer based in Brooklyn.