Abstract

The aim of this study was to examine the theory hypothesis suggested by the knowledge oriented approaches to cognitive development. We investigated 3- to 11-year-old children's physical, psychological and biological knowledge and examined whether they were organized as a theory, what kind of characteristics they had and how they have changed with increasing age. Results indicated that, for ontological distinctions, 3-year-old children performed correctly in about 25% of the tasks in each domain. This suggested that they had foundational abilities to form a theory. For causal law, from 5 years of age, children's physical, psychological and biological knowledge were used as a causal device to give explanations to why questions. For coherence, in psychological domain, coherence of knowledge system has emerged from 3 years of age, however in physical and biological domains, it has emerged after 9 and 11 years of age respectively. For abstract construct, in psychological domain, after 3 years of age, children explained behaviors by the abstract construct such as the state of mind. However, in physical and biological domains, not until at 9- and 11-year-old, children explained the causal relations by an abstract construct. The findings of the present study suggest that children's knowledge exists as a theory much earlier than known by the traditional theory and the theories of each domain develop specifically with increasing age.