Key word "psychological terminology"

The terms, period, phase, stage, and level – all frequent in the literature on development – are examined in order to specify conceptual differences. The authors suggest that while level has no inherent temporal component, the other three refer to stretches of time and should be differentiated according to whether or not they refer to (a) part of a progression; (b) a recurrent state or event; (c) quantitative change, and (d) qualitative change. The four terms can be distinguished as different combinations of the given criterial elements.

Key words: Developmental concepts, stage theories, conceptual analysis, semantics, qualitative change, psychological terminology