6 - Causal maps and Bayes nets: a cognitive and computational account of theory-formation

Summary

In this chapter, we outline a more precise cognitive and computational account of the ‘theory theory’ of cognitive development. Theories and theory-formation processes are cognitive systems that allow us to recover an accurate ‘causal map’ of the world: an abstract, coherent representation of the causal relations among events. This kind of knowledge can be perspicuously represented by the formalism of directed graphical causal models, or ‘Bayes nets’. Human theory formation may involve similar computations.

The theory theory

Cognitive psychologists have argued that much of our adult knowledge, particularly our knowledge of the physical, biological and psychological world, consists of ‘intuitive’ or ‘naïve’ or ‘folk’ theories (Murphy and Medin, 1985; Rips, 1989). Similarly, cognitive developmentalists argue that children formulate and revise a succession of such intuitive theories (Carey, 1985; Gopnik, 1988; Keil, 1989; Wellman, 1990; Gopnik and Meltzoff, 1997; Wellman and Gelman, 1997). This idea, which we have called the ‘theory theory’, rests on an analogy between everyday knowledge and scientific theories. Advocates of the theory theory have drawn up lists of features that are shared by these two kinds of knowledge. These include static features of theories, such as their abstract, coherent, causal, counter-factual-supporting character; functional features of theories such as their ability to provide predictions, interpretations and explanations; and dynamic features such as theory changes in the light of new evidence (see Gopnik and Wellman, 1994; Gopnik and Meltzoff, 1997).