Answer: Ishmael has a savant syndrome
Explanation: It is a syndrome that is characteristic of people who have a mental disorder and impairment, can show ability in the field of music, art in general, rapid computation, which are above average in these persons compared to others. Also, such persons are far more capable of operating and combining data such as calculating Christmas each year in this century or for jobs that contain a large amount of information that needs to be accurately and quickly set up and organised, such as map making. In one word, Ishmael and similar persons have a greater ability for memory than others.