The triarchic theory of (successful) intelligence explains in an integrative way the relationship between intelligence and (a) the internal world of the individual, or the mental mechanisms that underlie intelligent behavior; (b) experience, or the mediating role of the individuals’ passage through life between their internal and external worlds; and (c) the external world of the individual, or the use of these mental mechanisms in everyday life in order to attain an intelligent fit to the environment. The theory has three subtheories, one corresponding to each of the three relationships mentioned in the preceding sentence.