Police use forensic hypnosis to help witnesses and victims recall events otherwise lost in memories scarred by trauma.

"In traumatic experiences, such as rape, the human process is to block (trauma) out of the mind," Payne said. "They don't want to relive it."

Hypnosis places a person in a trance state that can resemble sleep, but is instead an altered state of consciousness more like a lucid dream.

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