Extrinsic characteristics. Theory in action The realistic theory in the Netherlands started as a response to mechanistic theory and to the ‘New Math’ movement in the 1960s. The various prototypes of the realistic theory are a result of adapting, modifying and expanding the previous versions. The designer uses and develops theory when he is working on designing and testing his teaching package. He develops theory as a reflection on his practice17 and makes use of the latest developments in domain-specific instructional theory. In Schön’s terminology (1983) we can speak of interaction between ‘theory on action’ and ‘theory in action.’ This is a cyclical process. The process of curriculum development, as we can see it in Ter Xxxxx’x work, but also with developers following him, can be named a ‘theory-led bricolage.’ The term has been used by Xxxxxxxxxxx (1994, p. 110) to describe such a process, namely as the creative work of a kind of ‘bricoleur’ (handyman) who brainstorms, invents, improves, adjusts and adapts continuously. He uses appropriate tools and materials, whatever is available, to realize a specific function. While such a process is theory-led, theory is also developed in it. In all facets of the process the views of the designers – including their views on the concept of theory itself – help to determine the dynamics of (the development of) the theory. The developmental process of the theory shows that it has been a process of trial and error, and that it involves continuous development, the theory is never done. Ter Xxxxx (2005) makes that point yet again when he analyzes the developments in teaching multiplication. He describes how Xxxxxxxxxxx’x view on memorization processes for learning arithmetic and mathematics developed. This refers to views that are still recognizable, at various levels and in different educational settings, views that have had a lasting influence on the development of theory in this field. Adoption of the theory The theory is influenced by a number of factors, which can make or break the adoption of theory. To begin with, there is the influence from other theories. This domain- specific instructional theory contains elements from mathematical theories and from theories of learning. What is unique is the way in which elements from domain-specific instructional theory, from didactical phenomenology and from learning theories are integrated.
