Intelligence and Experience
For convenience, experiences that bear on intelligence development are divided into seven categories: prenatal experience, family experience, school experience, university experience, job experience, experience in old age, and a seventh category, nutrients and toxins, which spans the life stages. Experiences at each stage are not independent, but instead function as contingent sieves that limit or expand readiness to profit from experience at subsequent stages. Operative all along the developmental continuum is a law of cumulative advantage in which the cognitively rich become richer still. Aptitudes, including intelligence, always represent both finished work and foundation, product and raw material, an achieved “quality or power that makes possible the development. . . of some further quality or power” (Snow, 1991, p. 250).