ABSTRACT
The following quotation includes a series of questions that most developmental psychologists will recognize as familiar, legitimate, and significant: "Is there an orderly and predictable pattern to the changes? Does succession reach a stable end point if given enough time? Do different patterns of succession lead to the same final stage? Conversely, can one initial stage of succession lead to different final stages? Are some stages of succession more fragile than others? Answers to these basic questions are needed before we can hope to answer more practical questions." Implicit within this series of questions are important distinctions between change and development. First, not all changes follow an orderly and predictable pattern. While development always involves change, not all changes are developmental. Second, developmental changes occur in order, in sequence, or in succession, following each other in time in a causal or logical relationship. Time is unidirectional, and so are developmental changes. Third, development proceeds from initial stages to different final stages. We recognize development because later stages are distinct from what was before. In sum, developmental changes are changes that are both irreversible and novel (Anderson, 1957; Nagel, 1957; Schneirla, 1957).
