The eight-function model provides a map to all of the functions in each personality type, helping us identify the most likely defenses and blind spots for our type so that the readers can choose to engage them or dispense with them as the situation warrants. From 1998 to 2002, McAlpine worked with his team on how to get at the archetypal energy constellating around each function in the eight-function model. The material gleaned from all of these sources was compiled into a software program called the Function-Archetype Decoder to facilitate editing and updating as more information accrued. The term “function-archetype” describes the characteristic way that a function expresses when combined with the emotional energy of an archetype. Each function position tends to carry the energy of an archetypal complex, but not all of these complexes are active in a given personality—these are only the most common complexes that a type is vulnerable to.