And he added that the rat research is looking at a special kind of memory called conditioning. This may work differently in humans than other kinds of memory, said McDaniel.
And what about young children? Do they erase memories like the rats? Memory research hasn't focused much on them, McDaniel said.
Herry said his findings do have possible implications for humans. According to him, more understanding about how to prevent memories from forming and sticking around in rats could help scientists figure out how to prevent unstoppable fear and anxiety in people.
Paul Sanberg, director of the University of South Florida College of Medicine's Center of Excellence for Aging and Brain Repair, agreed that's possible. "If they understand the molecular mechanism [of traumatic memories], they could maybe develop drugs to reduce symptoms in people who have pathological fear," he speculated.
Sanberg said he remains curious about one issue in all this: Why would evolution -- which preserves traits that help creatures survive -- give young animals the ability to forget traumatic events, but not older ones?
Learn more about memory from McGill University.
SOURCES: Mark McDaniel, Ph.D., psychology professor, Washington University, St. Louis; Cyril Herry, Ph.D., researcher, Friedrich Miescher Institute, Basel, Switzerland; and Paul Sanberg, Ph.D., director, University of South Florida College of Medicine's Center of Excellence for Aging and Brain Repair, Tampa; Sept. 4, 2009, Science
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