. These perspectives can be briefly summarized in terms of the following questions. Is a student’s knowledge most accurately represented as a coherent unified framework of theory-like character (e.g., Carey, 1999; Chi, 2005; Ioannides & Vosniadou, 2002; Wellman & Gelman, 1992)? Or is a student’s knowledge more

Many studies appear to show that categorization conforms to psychological essentialism (e.g., Gelman & Wellman, 1991). However, key implications of essentialism have not been scrutinized. These are that people’s categorizations should shift as their knowledge of micro-structural properties

causal knowledge about the world in a variety of domains. Children reason about the causes of mental states such as beliefs and desires (e.g. see Wellman, 1990), in the domain of physics, they reason about object properties and forces (e.g. Bullock, Gelman, & Baillargeon, 1982; Shultz, 1982

in spontaneous behavior. When the task demands are made simple enough, infants demonstrate implicit knowledge across diverse domains ranging from understanding of the physical world and numerical concepts to social cognition (see Wellman & Gelman 1998). In the domain of language understanding as well

young children have remarkably sophisticated causal knowledge about the world. Children reason about the causes of mental states (e.g., Meltzoff, 1995), physical systems (e.g., Bullock, Gelman, & Baillargeon, 1982; Shultz, 1982), and biological events (e.g., Gelman & Wellman, 1991; Kalish, 1996

it to a friend. By the preschool years, children understand this sequence by appealing to abstract theories of human action (Wellman & Gelman, 1992). For example, children can rely on their naïve theories of psychology to infer that underlying mental states motivate Jane’s behavior (e.g., that she

children's beliefs about causal relations (see Wellman & Gelman, in press, and 1992, for reviews). Representations of causal relations

& Liu, 2007), and children’s explanations may demonstrate a more sophisticated understanding than their answers (Legare, Wellman, & Gelman, 2009). Previous research on scientific reasoning within an oral health context (Croker & Buchanan, in press) shows that context, prior beliefs and a

together so many key issues concerned with how our concepts de-velop within larger sets of beliefs. One central theme has been domain specificity [Keil, 1981; Wellman & Gelman, 1992; Hatano & Inagaki, 2000]. A focus on bound-ed domains of thought, such as folkbiology, folkpsychology, or folkphysics