Cognitive Development in Children Reasons behind why children think in different ways have been established in various theories. Jean Piaget advanced a greatly influential theory that reflected his prior studies in the fields of biology and genetic epistemology. It is a theory that has been contended by many others, including that of the information-processing approach to cognitive development. It will be shown where these theories compare and where they contrast, in conclusion explaining why Mary's children think differently. Introduction The cognitive abilities of children have long been an issue for developmental psychologists. The development of a child's mental p