Cambridge University Press. In infancy, motor development stretches long into the early years of life, necessitating that young infants rely on their mothers almost entirely. The age or qualities assigned for each of these contexts are tied to culturally-significant indicators of independence that often vary as a result of social sentiments. The status of maturity is distinguished by the shift away from reliance on guardianship and the oversight of an adult in decision-making acts. Piaget's Theory of Intellectual Development. The incomplete development of this process contributes to the finding that adolescents use their brain less broadly than do adults when asked to inhibit a response and show less cross-talk communication across diverse regions of the brain. Categories : Developmental psychology. From Wikipedia, the free encyclopedia.