My EXNH had an unbelievable memory. He could remember details and dates like no one I had seen before. However, there was only one reason why he remembered these dates and that was to garner Narcissistic Supply.
It's a great question, Aceone Lady. Whether their memory is different than ours. The answer is yes. Studies tell us we have two different memories for the same situation. One is explicit memory - a memory of the details of the experience and the other is Implicit memory - a memory of the emotions connected to the experience. For example, smelling a baked apple pie reminds me of my Grandma and brings about an emotional response of missing her. That is implicit memory. Explicit memory would be my ability to remember how to make the pie. - the details of the experience.