Large Impassioned

Fifth, the capacity must have a unique developmental history for each individual, reflecting each person’s different level of mastery of it. Sixth, the intelligence must be measurable in psychometric studies that are reflective of differing levels of mastery across intelligences.

Third, case studies must exist that show that some subgroups of people (such as child prodigies) exhibit an elevated mastery of a given intelligence. Fourth, the intelligence must have some evolutionary relevance through history and across cultures.