There are several types of amnesia. “Dissociative fugue” (e.g., portrayed in the book/movie The Bourne Identity) is usually temporary and can be triggered by a very traumatic or stressful event. Rare, they affect less than 0.2% of people. (See multiple personality disorder. (On the Brain, newsletter. p 4. CA:2005.)

While amnesiacs have no conscious recollection of any new experience, they can learn many things nonconsciously (e.g., when given suggestions during surgery that they will recover quickly, they subsequently spend less time in the hospital than patients not given the suggestions, despite having no conscious memory of what was said while they were under anesthesia). (Wilson, Timothy D. Strangers to Ourselves. p 24-25. England: The Belknap Press of Harvard University Press, 2002.)