Development is a science that studies the changes and stability that occur in the human mind, body, and social relationships from birth to death. This includes physical and neurophysiological processes, cognition, language, emotion, personality, and psychosocial development.
Meta-theories of development: The assumptions that researchers hold about the nature of people and their development are called meta-theories. These are often the same assumptions that underlie many other sciences, including biology and psychology.
Continuity or Discontinuity: Some theories of development assume that humans change in a steady, continuous fashion. These theories are known as maturational meta-theories, and they are based on the assumption that human development follows a biological sequence just like that of a seed or an acorn.
Others, such as Freud, Erikson, Piaget, and Kohlberg, assume that developmental change is more discontinuous. These theorists believe that each stage of development is qualitatively different from each other and that the sequence of stages is a set, universal pattern that unfolds over time.
These theorists also assume that changes in development are shaped by both environmental (e.g., family history) and biological influences (e.g., brain development).
Theorists that endorse lifespan or ecological systems perspectives believe that developmental change takes place in a variety of patterns and pathways that are unique to the particular cultural, historical, and societal conditions under which it occurs. This type of development, which is referred to as human scale development, calls for an approach that respects the diversity of people and their autonomy in their local spaces, while encouraging a democratic society that enables popular participation in its own advancement and consolidation.