This study examined the development of the rational number concept as a ratio. Preliminary to the description of the study is an introduction discussing constructivism and equilibration. The study itself tests whether equilibration theory holds, and if so, what is the nature of its "phases" and whether these are found at each of the "periods" of…

This 4-year longitudinal study of logical reasoning found complex interrelationships among different cognitive processes of children ages 6 to 15. Piaget's stage theory is discussed in the introduction, with a focus on the concrete operational stage in middle childhood. In the study, a representative array of logical concept tasks and short-term…