Slipping on a pair of dark glasses, Agent Kay raises a mysterious handheld device before a crowd of shocked New Yorkers. Suddenly, the unit emits a brilliant flash of light that vaporizes all memory of a violent attack by space aliens from the minds of panicked earthlings who had just witnessed the horror. That little flashy thing, as Will Smith's character calls it in this scene from the movie Men in Black, is not entirely science fiction; neuroscientists know how to erase memories of the recent past, while leaving well-established memories intact. And new research suggests that even long-term memories could be deleted.
Erasing bad memories could be extremely therapeutic. Many people are haunted by painful experiences that cause lasting psychological problems. Forty-nine percent of rape victims suffer post-traumatic stress disorder (PTSD), as do 17 percent of people who survive serious vehicular accidents and 14 percent of those who unexpectedly lose a family member, according to the Posttraumatic Stress Disorder Alliance. Uncontrollable feelings of fear and horror can overwhelm sufferers. Devastating social and psychiatric complications can result, including depression, alcohol and drug abuse, and suicide. Persistent fatigue, digestive disorders and unexplained chronic pain are also common. Sleep may offer no solace, as the distressing events return in vivid, recurring nightmares.