Is it possible to permanently change your memories? A group of scientists thinks so. And their new techniques for altering memories are raising possibilities of one day treating people who suffer from phobias, post-traumatic stress disorder and other anxiety-related conditions.The goal of the research isn’t to erase memory outright, as depicted in popular movies over the years. That would raise ethical issues and questions of what would happen to associated memories, scientists say. Instead, “reducing or eliminating the fear accompanying the memory…that would be the ideal scenario,” says Roger Pitman, a psychiatry professor at Harvard Medical School who has done extensive work in this area.

Scientists used to believe memories are like snapshots on which the details are fixed once they are recorded. Now, many experts accept the view that memories are stored like individual files on a shelf; each time they are pulled down for viewing, they can be altered before being put back into storage. Altering a memory during the time it is off the shelf can create an updated memory that can be saved in place of the old one, scientists believe.