ABSTRACT
Developmental psychology today has come to be understood as simply “child psychology”. Originally, its meaning was quite different: “development” meant the study of systemic changes. Though most apparent in children, it could also be fruitfully applied to adults. Development was not so much a study of “stages” or “phases” of a process as what went on between them, the mechanisms driving and constraining change. In continuity with this definition of development as systemic transformation, Part III asks how the ability to create and use “signs” and “symbols” (as discussed in Parts I and II) develops in ontogeny.
