A frame is a hierarchy of nodes (Figure 10). The origin of this notation may be traced to the British psychologist Sir Frederic Bartlett, who introduced the notion of a schema in his famous study of memory (Bartlett 1932). During the 1970s researchers in artificial intelligence developed and applied frames for a variety of purposes, including computer-based representations of everyday human activities (Schank 1975; Schank and Abelson 1977) and vision (Minsky 1975; Brewer 2000). During the 1980s, the American cognitive psychologist Lawrence W. Barsalou introduced frames in his studies of ad hoc categories (Barsalou 1982, 1991), autobiographical memories (Barsalou 1988), and contextual variability in concept representations (Barsalou 1987, 1989; Barsalou and Billmann 1989). He extended and refined previous presentations of the frame notation to represent concepts (Barsalou 1992b; Barsalou and Hale 1993), calling his new approach ‘dynamic frames’. The present authors adopted his techniques in the 1990s and began to apply them to conceptual change in science and the implications of Kuhn's mature work (Andersen, Barker, and Chen 1996; Chen, Andersen, and Barker 1998; Barker, Chen, and Andersen 2003).

CONSTITUENTS OF DYNAMIC FRAMES

In the explanations that follow we will draw increasingly complex diagrams to represent frames, and we distinguish the concepts appearing in frames by capital letters when we mention them in the text. To represent a concept by a frame, one layer of nodes is selected to represent attributes of the concept.