From rituals of remembrance to Post-It notes, humans struggle to preserve memories. And no wonder. They are, after all, at the core of personal identity.

Sometimes overlooked in the rush to remember, however, is the value of forgetting. Although the research is in the early stages, scientists are investigating the process, necessity and potential advantages of discarding recollections.

"We'd be absolutely lost without our ability to forget," said Michael Anderson, an associate professor of cognitive neuroscience at the University of Oregon. "Just on a basic level, can you imagine if you couldn't constantly update your memory? Do you want 10 years worth of parking space memories and all your old phone numbers in your head?"

Much of the research is focused upon helping us deliberately forget specific events. Two methods - behavior changes and drugs such as beta blockers - have proved at least moderately successful, suggesting that certain memories can indeed be cast off. The benefits of perfecting such techniques are enormous, researchers say. Combat veterans, abused children, car crash victims, to name a few, could all be freed from severe emotional trauma by eliminating the offending memory, or at least the emotional pain associated with it, researchers say.

"We want to be able to keep the past from overly intruding on a patient's life," said Roger Pittman, a professor of psychiatry at Harvard Medical School, who has worked extensively with victims of post-traumatic stress disorder, or PTSD. "When it preoccupies someone so much they can't concentrate on their work, their families, their present lives, it can ruin them."

Pittman's research found that emergency room patients who were given beta blockers within six hours of a traumatic event were far less likely to develop PTSD than those who did not. The medication interferes with the brain's ability to properly establish a deeply embedded memory. The research was published last year in the Journal of Biological Psychiatry.

Cracking the code of traumatic memory storage poses one of the greatest challenges for researchers. Studies have shown that stressful events release powerful hormones inside the brain that ensure the episode will be vividly recalled. The more stressful, the more hormones flood the brain. From an evolutionary standpoint, the response is critical for survival, researchers say.

"That's why we can't remember where we were the morning of Sept. 10 but can on the morning of Sept. 11," Pittman said.