Mappers strive to form an integrated map of their knowledge and experience, and work to dynamically update this map as they learn and experience new things. Packers strive to build a flat knowledge base out of their experience. For a packer, consistency and integration are not so important as finding or bending the right piece of knowledge for a given situation. Mappers tend to be better able to construct new ideas and see patterns or solutions where packers might not.
Packers tend to be better at diligently pursuing systematic goals.
Mappers predominantly adopt the cognitive strategy of populating and integrating mental maps, then reading off the solution to any particular problem. They quickly find methods for achieving their objectives by consulting their maps. Packers become adept at retaining large numbers or knowledge packets. The distinction between Mappers and Packers far predates Carter. It has been known for many years in child development circles, especially when dealing with gifted children.